The application of the process may be illustrated by an example:

One hundred kilos. of waste jute scraps are first of all treated in the manner usually employed in the paper industry; 15 per cent. of quicklime is added, and they are treated for 10 hours at a pressure of 11/2 atmospheres. The scraps are then freed from water by means of a hydro-extractor, or a press, and finally saturated with chlorine in a gas chamber for 24 hours or less, according to the requirements of the case. Every 100 kilos. of jute requires 75 kilos. of hydrochloric acid (20 deg. B.) and 20 kilos. of manganese peroxide (78-80 per cent.).

The jute then takes an orange color, and is subsequently washed in a tank, a kilo. of caustic soda being added per 100 kilos. of jute; this amount of alkali is sufficient to dissolve the pigment, which colors the water flowing from the washer a deep brown. After washing, the jute can be completely bleached by the use of 5-7 kilos. of bleaching powder per 100 kilos. of jute.—Mon. de la Teinture.

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THE INDEPENDENT—STORAGE OR PRIMARY BATTERY—SYSTEM OF ELECTRIC MOTIVE POWER.[1]

[Footnote 1: Abstract of a paper read before the American Streel Railway Association, Oct. 23, 1891.]

By KNIGHT NEFTEL.

Owing to a variety of causes, the system which was assigned to me at the last convention to report on has made less material progress in a commercial way than its competitors.

PRIMARY BATTERIES.

So far, primary batteries have been applied only to the operation of the smallest stationary motors. Their application in the near future to traction may, I think, be entirely disregarded. Were it not a purely technical matter, it might be easily demonstrated, with our knowledge of electro-chemistry, that such an arrangement as an electric primary battery driving a car is an impossibility.

In view of the claims of certain inventors, I regret to be obliged to make so absolute a statement; but the results so far have produced nothing of value.

SECONDARY BATTERIES.

The application of secondary or storage batteries to electrical traction has been accomplished in a number of cities, with a varying amount of success. Roads equipped by batteries have now been sufficiently long in operation to allow us to draw some conclusions as to the practical results obtained and what is possible in the near future. The advantages which have been demonstrated on Madison Avenue, in New York; Dubuque, Iowa; Washington, D.C., and elsewhere, may be summarized as follows:

First. The independent feature of the system. The cars independent of each other, and free from drawbacks of broken trolley wires; temporary stoppages at the power station; the grounding of one motor affecting other motors, and sudden and severe strains upon the machinery at the power station, such as frequently occur in direct systems; the absence of all street structures and repairs to the same, and the loss by grounds and leakages, are also very considerable advantages, both as to economy and satisfactory operation.

Second. The comparatively small space required for the power station. Each car being provided with two or more sets of batteries, the same can be charged at a uniform rate without undue strain on the machinery of the power station, and as it can be done more rapidly than the discharge required for the operation of the motors, a less amount of general machinery is necessary for a given amount of work.

Another and important advantage of the system is the low pressure of the current used to supply the motors, and the consequent increased durability of the motor, and practically absolute safety to life from electrical shock.

It has been demonstrated also that the cars can be easily handled in the street; run at any desired speed, and reversed with far more safety to the armature of the motor than in the direct system. The increased weight requires simply more brake leverage.

The modern battery, improved in many of its details during the last year, is still an unknown quantity as to durability. There is the same doubt concerning this as there was at the time incandescent lamps were first introduced. At that time some phenomenal records were made by lamps grouped with other lamps.

Similarly, some plates appeared to be almost indestructible, while others, made practically in the same manner, deteriorate within a very short time. It is, consequently, very difficult to exactly and fairly place a limit on the life of the positive plates as yet. Speaking simply from observation of a large number of plates of various kinds, I am inclined to put the limit at about eight months; though it is claimed by some of the more prominent manufacturers—and undoubtedly it is true in special cases—that entire elements have lasted ten months, and even longer.

It must be remembered, however, that the jolting and handling to which these batteries are subjected, in traction work, increases the tendency to disintegrate, buckle and short circuit, and that the record for durability for this application can never be the same as for stationary work. A serious inconvenience to the use of batteries in traction work is the necessary presence of the liquid in the jars. This causes the whole equipment to be somewhat cumbersome, and unless arranged with great care, and with a variety of devices lately designed, a source of considerable annoyance.

The connections between the plates, which formerly gave so much trouble by breaking off, have been perfected so as to prevent this difficulty, and the shape of the jars has been designed to prevent the spilling of the acid while the car is running. The car seats are now practically hermetically sealed, so that the escaping gases are not offensive to the passengers.

The handling of the batteries is an exceedingly important consideration. Many devices have been invented to render this easy and cheap. I have witnessed the changing of batteries in a car, one set being taken out and a charged set replaced by four men in the short space of three minutes. This is accomplished by electrical elevators, which move the batteries opposite the car, and upon the platforms of which the discharged elements are again charged.

The general conclusions which the year's experience and progress have afforded us an opportunity to make may be summarized as follows:

Storage battery cars are as yet applicable only to those roads which are practically level; where the direct system cannot be used, and where cable traction cannot be used; and applicable to those roads only at about the same cost as horse traction.

I feel justified in making this statement in view of the guarantees which some of the more prominent manufacturers of batteries are willing to enter into, and which practically insure the customer against loss due to the deterioration of plates: leaving the question of the responsibility of the company the only one for him to look into.

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ON THE ELIMINATION OF SULPHUR FROM PIG IRON.[1]

[Footnote 1: Paper read before the Iron and Steel Institute.]

By J. MASSENEZ, Hoerde.

If in the acid and the basic Bessemer processes the molten pig iron is taken direct to the converter from the blast furnace, there is the disadvantage that the running of the individual blast furnaces can hardly ever be kept so uniform as it is desirable should be the case in order to secure regularity in the converter charges. In the manufacture of Bessemer steel the variable proportions of silicon and of carbon here come chiefly under consideration, while in the basic process it is chiefly the varying proportions of silicon and of sulphur; and in cases where either ores containing variable percentages of phosphorus, or puddle slags, are treated, the varying proportion of phosphorus has also to be considered. This disadvantage of the irregular composition of the individual blast furnace charges is obviated in a simple and effective manner by W.R. Jones's mixing process. In this as much pig iron from the various blast furnaces of a works as is sufficient for a large number of Bessemer charges, say from seven to twelve charges, or, in other words, from 70 to 120 tons of pig iron, is placed in a mixing vessel. Only a portion of pig iron placed in the mixer is taken for further treatment for steel, while new supplies of pig iron are brought from the blast furnace. In this way homogeneity sufficient for practical purposes is obtained.

In the treatment of phosphoric pig iron, which is employed in the production of basic steel, it is, however, not sufficient merely to conduct the molten pig iron in large quantities to the converter in a mixed condition, but the problem here is to render the proportion of sulphur also independent of the blast furnace process to such an extent that the proportion of sulphur in the finished steel is so low that the quality of the steel is in no way influenced by it. The question of desulphurization has, especially of late years, become of the utmost importance, at any rate for the iron industry of the Continent. By the great strike of 1889, the German colliers have succeeded in greatly improving their wages; and with this increase in wages not only is there a distinct diminution in the amount of coal wrought, but, unfortunately, the coal produced since then is raised in a much less pure condition than was formerly the case. Consequently the proportion of sulphur in the coke has considerably increased. Whereas formerly this proportion did not exceed one per cent., it has now in many cases risen to 18 per cent.; so that an unpleasant ratio exists between the wages of the workmen and the amount of sulphur in the coal raised. It is therefore not remarkable that, even when ores fairly free from sulphur are treated, it easily happens that a sulphureted pig iron is obtained.

In order to effect satisfactory desulphurization, attention has been bestowed on the fact that iron sulphide is converted by manganese into manganese sulphide and iron. If sulphureted pig iron, poor in manganese, is added in a fluid condition to manganiferous molten pig iron, poor in sulphur, the metal is desulphurized, and a manganese sulphide slag is formed. It may be urged that it does not seem necessary to effect the desulphurization by means of the reaction of the manganese and iron sulphide outside of the blast furnace, as it is possible, by suitably directing the blast furnace, by the employment of manganiferous ores or highly basic slag, so to desulphurize the iron in the blast furnace itself that it would be unnecessary further to lower the percentage of sulphur. Every blast furnace manager, however, will have observed that, even with every precaution in the blast furnace practice, pig iron will often be obtained with so high a percentage of sulphur as to render it useless for the Bessemer acid or basic processes. If the desulphurization in the blast furnace is carried sufficiently far, it is always necessary to work the furnace hot, and thus to obtain hotter iron than is desirable for further treatment in the converter. On the other hand, the method of further desulphurization outside the blast furnace, described in this paper, presents the double advantage that part of the blast furnace can be kept cooler, and thus lime and coke be saved, and that there is a certainty that no red-short charges are obtained in the treatment in the converter, while the pig iron passes to the converter at a suitable temperature.



A further advantage presented by the direct process described in this paper is that the Bessemer works is independent of the time at which the individual blast furnaces are tapped, as the pig iron required for the Bessemer process can be taken at any moment from the desulphurizing plant. In Hoerde, where the mixing and desulphurizing process has for a considerable time been regularly in use, it has been found that all the chief difficulties formerly encountered in the method of taking the fluid pig iron direct from the various blast furnaces to the converter have been obviated. At Hoerde the mixing and desulphurizing plant shown in the accompanying engravings is employed. This apparatus holds 70 tons of pig iron. It is, however, advisable to have an apparatus of greater capacity, say 120 tons. The apparatus has the shape of a converter, and the hydraulic machinery by which it is moved is simple and effective. An hydraulic pressure of eight atmospheres is sufficient to set it in motion. The vessel is provided with a double lining of firebricks of the same quality as those used for the lining of blast furnaces. This lining is gradually attacked only along the slag line, and does not require repair until it has been in use for some six weeks. Further repairs are then necessary every three weeks. Only the few courses of spoilt bricks are renewed, and for the repairs, including the cooling of the vessel, a period of two or three days is required. At the end of the week the vessel is kept filled, so that its contents suffice for the last charge to be blown on Saturday. On Sunday night the vessel is again filled. The consumption of manganese is very low; theoretically, it is the quantity required for the formation of manganese sulphide, and in practice it has been found that this amounts to about 0.2 per cent. The proportion of manganese which the desulphurized pig iron coming from the vessel should contain is best kept at about 1.5 per cent. in order to render the desulphurization as complete as possible. Thus, a mean proportion of 1.7 per cent. of manganese in the pig iron passing into the vessel is more than sufficient to effect a thorough desulphurization. Indeed, 1 to 1.2 per cent. of manganese is sufficient to effect a satisfactory desulphurization. For the extent of the removal of the sulphur, the temperature and the duration of the reaction are of importance. It has been found that if highly sulphureted pig iron is poured from the blast furnace into the desulphurizing vessel, fifteen to twenty minutes are sufficient to effect the desulphurization requisite for the steel process. The part played by the duration of the process is seen from the results obtained with the last charges, if the vessel is emptied at the end of the week without fresh pig iron being added from the blast furnace. If, for example, 60 tons of pig iron with 0.065 per cent. of sulphur remain in the vessel, the proportion of sulphur with the last charges falls to 0.03 per cent. The iron in the vessel remains sufficiently fluid for several hours. When necessary, a little wood is thrown in. It has been found quite unnecessary to obtain heat by passing and burning a current of gas above the bath of metal.

A number of results, showing the separation of sulphur at the Hoerde Works, was published a few months ago[2] by Professor P. Tunner, one of our honorary members.

[Footnote 2: "Oesterreichische Zeitschrift fur Berg und Huttenwesen," 1891, No. 19.]

The totals represent, respectively, 138,500 kilogrammes of pig iron and 98,654 kilogrammes of sulphur.

Thus, from 138,500 kilogrammes of pig iron there has been eliminated 179,577-98,654 = 80,923 kilogrammes of sulphur, or, in other words, 45.063 per cent.

The proportion of sulphur in the slags rises with that in the iron from the blast furnace to 17 per cent., an inappreciable portion of the sulphur of the slag being oxidized to sulphurous anhydride by access of air. An analysis of the slag yielded the following results:

Per cent. Sulphur 17.07 Manganese 30.31 Phosphoric anhydride 0.61 Iron 7.13 Bases 35.04

An analysis of an average sample gave:

Per cent. Manganese sulphide 28.01 Manganous oxide 20.23 Ferrous oxide 25.46 Silica 18.90 Alumina 5.00 Lime 3.53 Magnesia 0.43

The great convenience and certainty presented by the method described in this paper will in all probability lead to its general adoption. As a matter of fact, several works are now occupied with the installation of this mixing and desulphurizing plant.

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ON THE OCCURRENCE OF TIN IN CANNED FOOD.

By H.A. WEBER, Ph.D.

The following investigation of the condition of foods packed in tin cans was prompted by an alleged case of poisoning, which occurred at Mansfield, Ohio, in April, 1890. A man and woman were reported to the writer as having been made sick by eating pumpkin pie made from canned pumpkin. The attending physician pronounced the case one of lead poisoning. The wholesale dealer from whose stock the canned pumpkin originally came, procured a portion of the same at the house where the poisoning occurred, and sent it to the writer for examination.

The results of the examination as reported in Serial No. 552, below, showed that the canned pumpkin contained an amount of stannous salts equivalent to 6.4 maximum doses and 51.4 minimum doses of stannous chloride per pound. On being notified of this fact, the dealer sent a can of the same brand of pumpkin from his stock. The inner coating of the can was found to be badly eroded, and upon examination, as reported in Serial No. 563, below, one pound of the pumpkin contained tin salts equivalent to 7 maximum and 56 minimum doses of stannous chloride.

The unexpected large amount of tin salts in such an insipid article as canned pumpkin, and the claimed ill effects of the consumption of the same, suggested the advisability of extending the investigation to other canned goods in common use. Accordingly a line of articles was purchased in open market as sold to consumers, no pains being taken to procure old samples. The collection embraced fruits, vegetables, fish and condensed milk. With the exception of the condensed milk, every article examined was contaminated with salts of tin. In most cases the amount of tin salts present was so large that there can be no doubt of danger to health from the consumption of the food, especially if several kinds are consumed at the same meal.

METHOD.

The method employed in the determination of the tin was simply as follows:

The contents of each can were emptied into a large porcelain dish, and the condition of the inner coating of the can noted. After thoroughly mixing the contents, fifty grammes were weighed off and incinerated in a porcelain dish of suitable size. The residue was treated with a large excess of concentrated hydrochloric acid, evaporated to dryness, moistened with hydrochloric acid, water was added, and the mass was filtered and washed, the insoluble matter being all washed upon the filter. After drying the filter with its contents, the whole was again incinerated in a porcelain dish and the residue treated as before. The solution thus obtained was properly diluted and saturated with hydrogen sulphide. After standing about twelve hours in a covered beaker the precipitate was filtered off and the tin weighed as stannic oxide.

RESULTS OF EXAMINATION.

Serial No. 552.—Sample of canned pumpkin, received of F.A. Derthick, April 22, 1890, sent by Albert F. Remy & Co., Mansfield, Ohio. Pie made from it supposed to have made a man and woman sick. The attending physician pronounced the case one of lead poisoning.

Per cent. Tin dioxide with trace of lead 0.0424 Grains per pound 2.97 Equivalent to stannous chloride 3.74 Minimum doses 51.4 Maximum doses 6.4

Serial No. 563.—Sample of canned pumpkin, received of Edward Bethel, June 27, 1890. Labeled: Choice Pie Pumpkin, packed at Salem, Columbiana County, Ohio, by G.B. McNabb, sent by A.F. Remy & Co., Mansfield, Ohio.

Per Cent. Tin dioxide 0.0444 Grains per pound 3.11 Equivalent to stannous chloride 3.91 Minimum doses 56 Maximum doses 7

Can eroded.

Serial No. 565.—Sample of canned pumpkin, bought of T.B. Vaure, July 11, 1890. Labeled: Belpre Pumpkin, Golden. George Dana & Sons, Belpre, Ohio.

Per Cent. Tin dioxide 0.0054 Grains per pound 0.38 Equivalent to stannous chloride 0.48 Minimum doses 7.7 Maximum doses 1.0

Can eroded.

Serial No. 566.—Sample of canned Hubbard Squash, bought of T.B. Vaure, July 11, 1890. Labeled: Ladd Brand, L. Ladd, Adrian, Michigan.

Per Cent. Tin dioxide 0.026 Grains per pound 1.85 Equivalent to stannous chloride 2.33 Minimum doses 37.00 Maximum doses 4.7

Can badly eroded.

Serial No. 567.—Sample of canned tomatoes, bought of T.B. Vaure, July 11, 1890. Labeled: Extra Fine Tomatoes. Blue Label. Curtice Bros. Co., Rochester, N.Y.

Per Cent. Tin dioxide 0.012 Grains per pound 0.84 Equivalent to stannous chloride 1.06 Minimum doses 16.00 Maximum doses 2.00

Inner coating eroded.

Serial No. 568.—Sample of canned tomatoes, bought of T.B. Vaure, July 11, 1890. Labeled: Fresh Tomatoes, Curtice Bros. Co., Rochester, N.Y.

Per Cent. Tin dioxide 0.014 Grains per pound 0.98 Equivalent to stannous chloride 1.23 Minimum doses 19.00 Maximum doses 2.5

Can eroded.

Serial No. 569.—Sample of canned peas, bought of T.B. Vaure, July 11, 1890. Labeled: Petites Pois, P. Emillien, Bordeaux.

Per Cent. Copper oxide 0.0294 Grains per pound 2.06 Equivalent to copper sulphate 3.95 Tin dioxide 0.0068 Grains per pound 0.48 Equivalent to stannous chloride 0.6 Minimum doses 9.6 Maximum doses 1.2

No visible erosion.

Serial No. 570.—Sample of canned mushroom, bought of T.B. Vaure, July 11, 1890. Labeled Champignons de Choix. Boston fils. Paris.

Per Cent. Tin dioxide 0.02 Grains per pound 1.40 Equivalent to stannous chloride 1.76 Minimum doses 28.00 Maximum doses 3.50

Inner coating highly discolored.

Serial No. 571.—Sample of canned blackberries, bought of T.B. Vaure, July 11, 1890. Labeled: Lawton Blackberries. Curtice Bros. Co., Rochester, N.Y.

Per Cent. Tin dioxide 0.0114 Grains per pound 0.80 Equivalent to stannous chloride 1.01 Minimum doses 16.00 Maximum doses 2.00

Inner coating eroded.

Serial No. 572.—Sample of canned blueberries, bought of T.B. Vaure, July 11, 1890. Labeled: Blueberries. Eagle Brand, packed by A. & R. Loggie, Black Brook, N.B.

Per Cent. Tin dioxide 0.03 Grains per pound 2.10 Equivalent to stannous chloride 2.64 Minimum doses 42.00 Maximum doses 5.30

Can badly eroded.

Serial No. 574.—Sample of canned salmon, bought of T.B. Vaure. July 11, 1890. Labeled: Best Fresh Columbia River Salmon, Eagle Canning Co., Astoria Clatsop Co., Oregon.

Per Cent. Tin dioxide 0.0134 Grains per pound 0.94 Equivalent to stannous chloride 1.18 Minimum doses 18.90 Maximum doses 2.30

Inner coating eroded.

Serial No. 578.—Sample of canned pears, received of Mr. Edward Bethel, July 29, 1890. Labeled: Bartlett Pears. Solan's Brand, packed in Solano Co., California.

Juice. Fruit. Per Ct. Per Ct. Tin dioxide 0.0074 0.0074 Grains per pound 0.5180 0.5180 Equivalent to stannous chloride 0.65 0.65 Minimum doses 10.40 10.40 Maximum doses 1.30 1.30

Can eroded.

Serial No. 579.—Sample of canned peaches, received of Edward Bethel, July 29. 1890. Labeled: Peaches, Wm. Maxwell, Baltimore, U.S.A.

Juice. Fruit. Per Ct. Per Ct. Tin dioxide 0.0324 0.0414 Grains per pound 2.2680 2.8980 Equivalent to stannous chloride 2.85 3.65 Minimum doses 45.60 58.40 Maximum doses 5.70 7.30

Can badly eroded.

Serial No. 580.—Sample of canned blackberries, received of Edward Bethel, July 29, 1890. Labeled: Blackberries, Clipper Brand, Wm. Munson & Sons, Baltimore, Md.

Per Cent. Tin dioxide 0.06 Grains per pound 4.20 Equivalent to stannous chloride 5.28 Minimum doses 84.00 Maximum doses 10.60

Can badly eroded.

Serial No. 581.—Sample of canned cherries, received of Edward Bethel, July 29, 1890. Labeled: Red Cherries, Cloverdale Brand, G.C. Mournaw & Co., Cloverdale, Va.

Per Cent. Tin dioxide 0.0414 Grains per pound 2.8980 Equivalent to stannous chloride 3.65 Minimum doses 58.40 Maximum doses 7.30

Can badly eroded.

Serial No. 582.—Sample of canned pumpkin, received of Edward Bethel, July 29, 1890. Labeled: Royal Pumpkin, Urbana Canning Co., Urbana, O.

Per Cent. Tin dioxide 0.0184 Grains per pound 1.2990 Equivalent to stannous chloride 1.62 Minimum doses 25.90 Maximum doses. 3.20

Can eroded.

Serial No. 583.—Sample of canned baked sweet potatoes, received of Edward Bethel, July 29, 1890. Labeled: Tennessee Baked Sweet Potatoes, Capital Canning Co., Nashville, Tenn.

Per Cent. Tin dioxide 0.0132 Grains per pound 0.92 Equivalent to stannous chloride 1.16 Minimum doses 18.50 Maximum doses 2.30

Can eroded.

Serial No. 584.—Sample of canned peas, received of Edward Bethel, July 29, 1890. Labeled: Marrowfat Peas, Parson Bros., Aberdeen, Maryland.

Per Cent. Tin dioxide 0.0044 Grains per pound 0.30 Equivalent to stannous chloride 0.38 Minimum doses 6.20 Maximum doses 0.80

Can slightly eroded.

Serial No. 585.—Sample of string beans, received of Edward Bethel, July 29, 1890. Labeled: String Beans. Packed by H.P. Hemingway & Co., Baltimore City, Md.

Per Cent. Tin dioxide 0.0154 Grains per pound 1.08 Equivalent to stannous chloride 1.36 Minimum doses 21.70 Maximum doses 2.70

Can eroded.

Serial No. 586.—Sample of canned salmon, received of Edward Bethel, July 29, 1890. Labeled: Puget Sound Fresh Salmon, Puget Sound Salmon Co., W.T.

Per Cent. Tin dioxide 0.0044 Grains per pound 0.30 Equivalent to stannous chloride 0.38 Minimum doses 0.20 Maximum doses 0.80

Can slightly eroded.

Serial No. 587.—Sample of condensed milk, received of Edward Bethel, July 29, 1890. Labeled: Borden's Condensed Milk. The Gail Borden Eagle Brand, New York Condensed Milk Co., 71 Hudson Street, New York.

Tin dioxide none.

No visible erosion.

Serial No. 592.—Sample of canned pineapples, bought of Mr. Brown, Fifth Avenue, August 4, 1890. Labeled: Pineapples, First Quality. Packed by Martin Wagner & Co., Baltimore, Md.

Per Cent. Tin dioxide 0.0098 Grains per pound 0.6860 Equivalent to stannous chloride 0.8640 Minimum doses 13.6 Maximum doses 1.7

Can eroded

Serial No. 593.—Sample of canned pineapples, bought of Mr. Brown, Fifth Avenue, August 4, 1890. Labeled: Florida Pineapple, Oval Brand. Extra Quality. A Booth Packing Co., Baltimore, Md.

Per Cent. Tin dioxide 0.0158 Grains per pound 1.11 Equivalent to stannous chloride 1.40 Minimum doses 22.40 Maximum doses 2.80

Can eroded.

—Jour. Amer. Chem. Soc.

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NEW PROCESS FOR THE MANUFACTURE OF CHROMATES.

By J. MASSIGNON and E. VATEL.

The ordinary method of manufacturing the bichromates consists in making an intimate mixture of finely pulverized chrome ore, lime in large excess, potash or soda, or corresponding salts of these two bases. This mixture is placed in a reverberatory furnace, and subjected to a high temperature, while plenty of air is supplied. During the operation the mass is constantly puddled to bring all the particles into contact with the hot air, so that all the sesquioxide of chromium of the ore will be oxidized. After the oxidation is finished, the mass is taken from the furnace and cooled; the bichromate is obtained by lixiviation, treated with sulphuric acid and crystallized. This method of manufacture has several serious objections.

The authors, after research and experiment, have devised a new process, following an idea suggested by Pelouze.

The ore very finely pulverized is mixed with chloride of calcium or lime, or carbonate of calcium, in such proportions that all the base, proceeding from the caustic lime or the carbonate of calcium put in the mixture, shall be in slightly greater quantity than is necessary to transform into chromate of calcium all the sesquioxide of chromium of the ore, when this sesquioxide will be by oxidation changed into the chromic acid state. The chloride of calcium employed in proportion of one equivalent for three of the total calcium is most convenient for the formation of oxychloride of calcium. If the mixture is made with carbonate of lime (pulverized chalk), it will not stiffen in the air; but if lime and carbonate of calcium are employed at the same time, the mass stiffens like cement, and can be moulded into bricks or plates. The best way to operate is to mix first a part of the ore and well pulverized chalk, and slake it with the necessary concentrated chloride of calcium solution; then to make up a lime dough, and mix the two, moulding quickly. The loaves or moulds thus formed are partially dried in the air, then completely dried in a furnace at a moderate temperature, and finally baked, to effect the reduction of the carbonate of calcium into caustic lime. It is only necessary then to expose the loaves to the air at the ordinary temperature, for the oxidation of the sesquioxide of chromium will go on by degrees without any manipulation, by the action of the atmospheric air, the matter thus prepared having a sufficient porosity to allow the air free access to the interior of the mass. Under ordinary conditions the oxidation will be completed in a month. The division of this work—mixing, slaking or thinning, roasting or baking, and subjection to the air—is analogous to the work of a tile or brick works. The advance of the oxidation can be followed by the appearance of the matter, which after baking presents a deep green color, which passes from olive green into yellow, according to the progress of calcium chromate formation. When the oxidation is completed, the mass contains: Chromate of calcium, chloride of calcium, carbonate of lime and caustic lime in excess, sesquioxide of iron and the gangue, part of which is united with the lime. This mass is washed with water by the ordinary method of lixiviation, and there is obtained a concentrated solution containing all the chloride of calcium, and a small quantity only of chromate of calcium, the latter being about 100 times less soluble in water.

This solution can be used in the following ways:

1. It can be concentrated and used in preparing a new charge, the small quantity of calcium chromate present being an assistance, or:

2. It can be used for making chromate of lead (chrome yellow), by precipitating the calcium chromate with a lead salt; this being a very economical process for the manufacture of this color.

The mass after lixiviation, being treated with a solution of sulphate or carbonate of potash or soda, will yield chromate of potash or soda, and by the employment of sulphuric acid, the corresponding bichromates. The solutions are then filtered, to get rid of the insoluble deposits, concentrated, and crystallized.

If, instead of chromate or bichromate of potash or soda, chromic acid is sought, the mass after lixiviation is treated with sulphuric acid, and the chromic acid is obtained directly without any intermediate steps.

This process has the following advantages:

1. The oxidation can be effected at the ordinary temperature, thus saving expense in fuel.

2. The heavy manual labor is avoided.

3. The loss of potash and soda by volatilization and combination with the gangue is entirely avoided.

4. It is not actually necessary to use rich ores; silicious ores can be used.

5. The intimate mixture of the material before treatment being made mechanically, the puddling is avoided, and in consequence a greater proportion of the sesquioxide of chromium in the ores is utilized.—Bull. Soc. Chem. 5, 371.

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A VIOLET COLORING MATTER FROM MORPHINE.

A violet coloring matter is formed, together with other substances, by boiling for 100 hours in a reflux apparatus a mixture of morphine (seven grammes), p-nitrosodimethylaniline hydrochloride (five grammes), and alcohol (500 c.c.). The solution gradually assumes a red brown color, and a quantity of tetramethyldiamidoazobenzene separates in a crystalline state. After filtering from the latter, the alcoholic solution is evaporated to dryness, and the residue boiled with water, a deep purple colored solution being so obtained. This solution, which contains at least two coloring matters, is evaporated almost to dryness, acidulated with hydrochloric acid, and then rendered alkaline with sodium hydrate, the coloring matters being precipitated and the unchanged morphine remaining in solution. The precipitate is collected on a filter, washed with dilute sodium hydrate, dried, and extracted in the cold with amyl alcohol, which dissolves out a violet coloring matter, and leaves in the residue a blue coloring matter or mixture of coloring matters. The violet coloring matter is obtained in a pure state on evaporating the amyl alcohol. Its platinochloride has the formula PtCl_{4}.C_{25}H_{29}N_{3}O_{4}.HCl, and has the characteristic properties of the platinochlorides of the majority of alkaloids. The coloring matter, of which the free base has the formula—

(C_{6}H_{4}N(CH_{3})_{2})—N==(C_{17}H_{19}NO_{4})

forms an amorphous mass with a bronze-like luster; it is sparingly soluble in water, freely so in alcohol, its alcoholic solution being strongly dichroic; its green colored solution in concentrated sulphuric acid becomes successively blue and violet on dilution with water; it dyes silk, wool, and gun cotton, but is not fast to light.

Morphine violet is the first true coloring matter obtained from the natural alkaloids, the morphine blue of Chastaing and Barillot (Compt. Rend., 105, 1012) not being a coloring matter properly so called. —P. Cazeneuve, Bull. Soc. Chim.

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LIQUID BLUE FOR DYEING.

The new liquid blue of M. Dornemann is intended to avoid the formation of clots, etc., which lead to irregularity in shade, if not to the formation of spots on the textile. In addition to accomplishing this end, the process is accelerated by subjecting the blue to a previous treatment.

In this preliminary treatment of the blue, the object is to remove the sulphur which retards the solution of the color.

The liquid is prepared as follows: The pigment, previously dried at 150 deg. C., is crushed and finely ground, and contains about 47 per cent. of coloring matter; to this is added 53 per cent. of water.

To this mixture, or slurry, the inventor adds an indefinite quantity of glucose and glycerine of 43 deg. B., having a specific gravity of 1.425. It is then ready for use.—Le Moniteur de la Teinture.

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THE SCIENTIFIC AMERICAN

ARCHITECTS AND BUILDERS EDITION.

$2.50 A YEAR. SINGLE COPIES, 25 CTS.

This is a Special Edition of the SCIENTIFIC AMERICAN, issued monthly—on the first day of the month. Each number contains about forty large quarto pages, equal to about two hundred ordinary book pages, forming, practically, a large and splendid MAGAZINE OF ARCHITECTURE, richly adorned with elegant plates in colors and with fine engravings, illustrating the most interesting examples of modern Architectural Construction and allied subjects.

A special feature is the presentation in each number of a variety of the latest and best plans for private residences, city and country, including those of very moderate cost as well as the more expensive. Drawings in perspective and in color are given, together with full Plans, Specifications, Costs, Bills of Estimate, and Sheets of Details.

No other building paper contains so many plans, details, and specifications regularly presented as the SCIENTIFIC AMERICAN. Hundreds of dwellings have already been erected on the various plans we have issued during the past year, and many others are in process of construction.

Architects, Builders, and Owners will find this work valuable in furnishing fresh and useful suggestions. All who contemplate building or improving homes, or erecting structures of any kind, have before them in this work an almost endless series of the latest and best examples from which to make selections, thus saving time and money.

Many other subjects, including Sewerage, Piping, Lighting, Warming, Ventilating, Decorating, Laying out of Grounds, etc., are illustrated. An extensive Compendium of Manufacturers' Announcements is also given, in which the most reliable and approved Building Materials, Goods, Machines, Tools, and Appliances are described and illustrated, with addresses of the makers, etc.

The fullness, richness, cheapness, and convenience of this work have won for it the LARGEST CIRCULATION of any Architectural publication in the world.

A Catalogue of valuable books on Architecture, Building, Carpentry, Masonry, Heating, Warming, Lighting, Ventilation, and all branches of industry pertaining to the art of Building, is supplied free of charge, sent to any address.

MUNN & CO., PUBLISHERS, 361 BROADWAY, NEW YORK.

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BUILDING PLANS AND SPECIFICATIONS.

In connection with the publication of the BUILDING EDITION of the SCIENTIFIC AMERICAN, Messrs. Munn & Co. furnish plans and specifications for buildings of every kind, including Churches, Schools, Stores, Dwellings, Carriage Houses. Barns, etc.

In this work they are assisted by able and experienced architects. Full plans, details, and specifications for the various buildings illustrated in this paper can be supplied.

Those who contemplate building, or who wish to alter, improve, extend, or add to existing buildings, whether wings, porches, bay windows, or attic rooms, are invited to communicate with the undersigned. Our work extends to all parts of the country. Estimates, plans, and drawings promptly prepared. Terms moderate. Address

MUNN & CO., 361 BROADWAY, NEW YORK.

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THE

SCIENTIFIC AMERICAN SUPPLEMENT.

PUBLISHED WEEKLY.

TERMS OF SUBSCRIPTION, $5 A YEAR.

Sent by mail, postage prepaid, to subscribers in any part of the United States or Canada. Six dollars a year, sent, prepaid, to any foreign country.

All the back numbers of THE SUPPLEMENT, from the commencement, January 1, 1876, can be had. Price, 10 cents each.

All the back volumes of THE SUPPLEMENT can likewise be supplied. Two volumes are issued yearly. Price of each volume, $2.50 stitched in paper, or $3.50 bound in stiff covers.

COMBINED RATES.—One copy of SCIENTIFIC AMERICAN and one copy of SCIENTIFIC AMERICAN SUPPLEMENT, one year, postpaid, $7.00.

A liberal discount to booksellers, news agents, and canvassers.

MUNN & CO., PUBLISHERS 361 Broadway, New York, N.Y.

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USEFUL ENGINEERING BOOKS

Manufacturers, Agriculturists, Chemists, Engineers, Mechanics, Builders, men of leisure, and professional men, of all classes, need good books in the line of their respective callings. Our post office department permits the transmission of books through the mails at very small cost. A comprehensive catalogue of useful books by different authors, on more than fifty different subjects, has recently been published, for free circulation, at the office of this paper. Subjects classified with names of author. Persons desiring a copy have only to ask for it, and it will be mailed to them. Address,

MUNN & CO., 361 BROADWAY, NEW YORK.

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PATENTS!

MESSRS. MUNN & CO., in connection with the publication of the SCIENTIFIC AMERICAN, continue to examine improvements, and to act as Solicitors of Patents for Inventors.

In this line of business they have had forty-five years' experience, and now have unequaled facilities for the preparation of Patent Drawings, Specifications, and the prosecution of Applications for Patents in the United States, Canada, and Foreign Countries. Messrs. Munn & Co. also attend to the preparation of Caveats, Copyrights for Books, Labels, Reissues, Assignments, and Reports on Infringements of Patents. All business intrusted to them is done with special care and promptness, on very reasonable terms.

A pamphlet sent free of charge, on application, containing full information about Patents and how to procure them; directions concerning Labels, Copyrights, Designs, Patents, Appeals, Reissues, Infringements, Assignments, Rejected Cases. Hints on the Sale of Patents, etc.

We also send, free of charge, a Synopsis of Foreign Patent Laws, showing the cost and method of securing patents in all the principal countries of the world.

MUNN & CO., SOLICITORS OF PATENTS, 361 Broadway, New York.

BRANCH OFFICES.—No. 622 and 624 F Street, Pacific Building, near 7th Street, Washington, D.C.

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