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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
b u t clearly rose-colored, being even stronger than No. I before the addition of arsenic. The glass became slightly transparent 30 minutes later, but the red color had disappeared; after another half-hour there still remained some unfused matter, but otherwise the glass was clear, although i t possessed a greenish tint. An addition of 0.5 gram arsenic was now made, and the result was a clouded and intensely green colored glass; the green color persisted until clear fusion. Another addition of 0.5 gram arsenic gave a pale but still green glass. These fusions showed, as in the case of No. 11, t h a t soda-lime glass was hardly suited for selenium coloring, even though the greater lime content as compared t o the soda present, was somewhat favorable for coloring a t lirst. The increase in depth of the green color after the addition of arsenic was ascribed to a reduction of ferric silicate. No. IV.--roo grams quartz, 65 grams potash, and 31 grams calcium carbonate were fused with 0.5 gram selenium. The iron oxide (from the rod) altered the red cdlor of the selenium. An addition of 0.5 gram arsenic brightened the glass, and further additions served to produce ferrous oxide, the green color of which, with the red color of the selenium, produced the decolorization. The cold glass was bright yellow-brown, although i t had a rose tint. No. V.-The batch contained 100 grams quartz, 65 grams potash, and 60 grams barium carbonate, making a glass which fused easily: 0.5 gram selenium was added, and before fusion a n addition of 1.5 grams arsenicwasmade. After 2 hours, the glass was bright and possessed a coffee-brown color and a rose shade. After 30 minutes, I gram arsenic m-as added, whereupon the glass rapidly became colorless, with only a weak brown tint. Further additions of arsenic produced a green color. The arsenic had finally caused a complete reduction of ferric oxide to ferrous oxide and consequently a green color; the selenium had been volatilized, although probably barium selenide was iormed to a certain extent. No. VI.-The batch contained IOO grams quartz, 50 grams calcined soda, 60 grams barium carbonate, and 0.5 gram selenium. The addition of arsenic was made as in No. V. The first result was a n orange-brown, crystalline glass; after another addition of arsenic (I gram), i t became colorless. The complementary effects of the colors entered in here, for on repeated additions of I gram arsenic, the glass became very green colored. No. VI1.-The fusion was made with IOO grams quartz, 65 grams potash, 2 5 grams zinc oxide, and 0.5 gram selenium. After z1/2 hours, the glass was clear and of a deep brownish yellow color. The addition of arsenic failed to produce a change in color after 15 minutes; a second addition gave rise t o a yellowish gray tint; and a third addition caused no change but a slight brightening. Kraze was led t o believe t h a t zinc selenide was formed in this experiment. No. VIII.-IOO grams quartz, 50 grams calcined soda, 2 5 grams zinc oxide, and 0.5 gram selenium. The results obtained were similar to those in No. VII, except that the clarification occurred after 3 hours and the color changes were different. After the first addition of arsenic, the color change was to yellow, and further additions effected no change in color and only a slight clarification. A red tint was never noticed. The following tests were decidedly more acid than the preceding and the glasses were similar to potassium glasses of the type: 1.49 K2O.R0.g.8 acid. I n the previous tests the acids entered into the composition solely as silica; in the following difficultly fusible, acid glasses were experimented with for comparison. No. 1X.-This was a composition for Bohemian crystal glass taken from Hohlbaum’s “Zeir!gem&se Herstellung, Bearbeitung u n d Verzierung des feineren Hohlghses.” The batch of 100 grams quartz, 35 grams potash, and 17 grams calcium
July,
1912
carbonate was fused with only 0.1 gram selenium. Three hours after heating the furnace, test I showed no unfused parts and was deep brown, 2 hours after, tests 2 and 3 possessed the same color. The addition of 0.5 gram arsenic, however, caused a change to a pretty red (test 4). The rose color did not change after 3/, hour (test j ) , and even remained after repeated additions ( 2 . 5 grams) of arsenic (test 6). Even after 30 minutes later, following an addition of arsenic (0.5 gram), no change in color was observed. The results of this experiment showed t h a t the desired color had been obtained with very small amounts of selenium (0.1gram). Hence the results agreed with those of No. I, for the measured addition of sodium selenate (40 per cent. salt) used in the latter corresponded to 0 . 1 2 gram selenium; but glass No. I, with less silica, did not assume a rose color so rapidly as No. I X . Therefore, i t seems that the acid content of the glass plays a n important part in developing the red color. Nevertheless, it must not be considered that sodium selenate requires more energetic reduction for red coloring than selenium. Kraze also fused the batch of No. IX with 0.2 gram of selenium, with I gram selenium, and again with double and five times the amount. What he expected did not occur: he red coloration did not become intensified from an increase in the selenium content, and the rose color resulting from an addition of 0.1 gram selenium could not be distinguished from that from 0.2 gram selenium-in fact, both glasses were colored even more strongly than n-hen 0.5 gram selenium was used. No. X.-In this experiment lime was substituted by barium oxide, but otherwise the glass was the same. The batch was: IOO grams quartz, 35 grams potash, 33 grams barium carbonate, and 0 . 2 gram selenium. The first test had hardly been fused before it showed a rose tint. Two hours after the gas oven was started, the glass was thoroughly fused, but the rose color was brown tinted. Four hours later, tests showed t h a t the product was somewhat brighter. No. XI.-A more acid zinc glass than No. VI1 was obtained by substituting zinc oxide for barium oxide. .The batch consisted of IOO grams quartz, 35 grams potash, 14 grams zinc oxide, and 0.2 gram selenium. Tests showed that a t the beginning of the fusion there was a very weak rose tint, b u t the melt later became absolutely colorless; the addition of arsenic did not cause the least coloration. IOO grams quartz, 35 grams potash, No. XI1.-Composition: 39 grams minium, and 0.2 gram selenium. After 4 hours fusion, the tests showed a yellow glass, b u t later brownish yellow, and finally a glass colored a little more intensely. The next three experiments were again with potassium-lime glasses, but boric acid, phosphoric acid, or stannic oxide was in part substituted. Replacement of part of the silicic by boric acid in the acid potash glasses diminished the red color; and phosphoric acid and stannic oxide acted in a similar manner and to a greater extent. Replacement of the lime by fluorspar gave only a colorless glass, owing, no doubt, to the volatilization of t h e selenium as fluoride during the fusion. Kraze promises to investigate the existence of selenides in colored selenium glasses.
HEAVY OIL ENGINES.
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The following is a n abstract of a n address by Capt. H. R. Sankey before the Royal Society of Arts, April 29, 1912:Some twenty years ago there was only one form of oil engine, of which the Hornsby-Akroyd and Priestman could be taken as types. These engines required external heat a t starting for the evaporation of their fuel and worked on paraffin. I n 1890, Daimler invented the petrol-engine, which worked with petrol of a specific gravity of about 0.68 and which required no external heat for the evaporation of its fuel. Seven years later Diesel introduced his engine, which worked with heavy oil and required no external heat, as the fuel was mechanically “pulverized’’ instead of being evaporated.
July, 1912
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
At the present time, two classes of oil-engines are in use, wz.: light-oil engines, which use fuel capable of forming explosive mixtures a t ordinary temperatures and possessing a density of 0.68-0.72; and heavy-oil engines, which use fuel requiring high temperatures or mechanical “pulverization” for the formation of explosive mixtures, and possessing a specific gravity of 0.80.9. Of the heavy-oil class, the Diesel engine, which has received much space lately in the technical press, is the most important type. In it the compression occurs entirely on a charge of air, into which the fuel is afterwards injected, so that there is no danger of pre-ignition, and compression pressures up t o 450--500lbs. per sq. in. can be used. It is, in fact, in its high compression t h a t the great efficiency of the Diesel engine lays. I n the semi-Diesel type of engine, in iyhich, after compression of air, the fuel is injected into a hot bulb, there is no danger of pre-ignition, but compressions up to about zoo lbs. per sq. in. are usually found to be sufficient to ensure ignition. In the Diesel engine admission occurs a t constant pressure and exhaust a t constant volume, as compared with the gasengine and petrol-engine, in which admission takes place a t constant volume. This difference gives the Diesel engine a n advantage, since there is a greater difference between the upper portions of the actual and theoretical diagrams in the two cases. The economy of the Diesel engine is also largely accounted for by the high compressions, up to from 4jo-joo lbs. per sq. in., which can be used. The temperature reached in the cylinder of a Diesel engine is usually about 1 2 0 0 ~F. With a 2-stroke cycle gas-engine there is danger that some of the new working charge may be blown out of the exhaust by the scavenging air, but in a Diesel engine this can not happen, so that the Diesel may be regarded as essentially a n-stroke engine. According to Industrial Engineering, 11, 401,the thermal or indicated efficiency of the Diesel engine of to-day reaches 48 per cent., while the effective or brake efficiency reaches, in some cases, 3.j per ccnt. of the heat value of the fuel. This engine converts the heat of the natural fuel into work in the cylinder itself, without any previous transforming process. Allner (1. Gasbel., 54, 321) reported that tests on a IOO h. p. Diesel motor showed vertical-oven tar was a very satisfactory fuel for this type of engine; later (Progressive .4ge, 29, 481) it was pointed out that tar fuel was the least expensive for Diesel engines and t h a t lvith slight changes in the engine, no difficulty was experiencecl in using i t ; and Allner has more Gasbel., 54, 1025) that the present recently pointed out (1. practice in using tar is to assist ignition by spurting into the cylinder about j per cent. of gas oil just ahead of the tar. Recently, however, i t has been found possible t o operate on tar oil and avoid the use of even this small amount of gas oil, and quite lately it has been ascertained t h a t a 40 h. p. Diesel engine may be operated by the use of raw tar itself, using both vertical oven tar and certain kinds of retort oven tar, and wholly avoiding any use of ignition oil.
THE CLASSIFICATION OF SOAPS. With the object of classifying different soaps on a commercial scale, the Commission appointed by the Italian Union of Soap Makers has proposed to divide them in the order of their requirements. Gianoli reports as follows concerning the rec50,, 465 ommendations of the Commission [Chent. Trade I. (1912)l: I. PCRE SOAPS OF THE FINEST QUALITY.
( a ) Boded Soaps.-Hard, soft, floating, white and dyed, scented or unscented; not liable to change color or to become rancid; completely soluble in water and in alcohol; and constituted by a combination of soda and fatty acids when this is insoluble in sodium chloride solutions a t 1 5 O Be., i. e . , free from oxy-fatty acids, and in which the total percentage of hydrated fatty acids., non-siccative, is not less than 60 per cent.
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Free from unsaponified glycerides, hydrocarbons, wax, alkaline and metallic soaps; not more than 0.3 per cent. free sodium hydroxide; not more than I j per cent. total mineral matter, not more than 2 per cent. foreign organic matter (coloring matter, perfume, or fatty acids of low- molecular weight). (b) Resin Soaps.-Boiled with not more than I j per cent. of colophony, and otherwise corresponding to the requirements assigned t o the preceding. (c) ;Mottled and Marbled Soaps, in which the proportion of hydrated fatty acids is not less than 55 per cent., and the total free alkalies, carbonates, sulphates, and alkaline silicates do not exceed 3.5 per cent. 2.
CURREST SOAPS OF INFERIOR QUALITY.
Hard or soft, plain or marbled, containing, or not containing, alkaline mineral detergents, organic or mineral fillings in quantities greater than 3.j per cent. when the soaps contain 33 per cent. humidity-namely, soaps containing carbonates and alkaline silicates, talc, kaolin, asbestine, fossil flour, or sugar, starch, fecula, hydrocarbons, etc. Soaps manufactured cold or hot with f a t t y acid or glycerides of any nature, with or without resin. 3. DRY SOAPS. Soaps which do not give more than 2 0 per cent. of water when exposed for 3 hours t o a temperature of Ioj-110~C. after being pulverized with I O times their weight of powdered glass. The soap classifications hitherto published have been generally based on the methods of manufacture. The above classification seemed to the Italian Commission to more nearly meet the requirements of the analyst and consumer. What the latter desires to know is the peculiar charac.ter of the soap he is buying, and not how it is made. Consequently, to satisfy the trade, the limits within which the composition may vary must be specified.
THE SPONTANEOUS COMBUSTION OF CHARCOAL. I n 1911,there were 64 reported fires in the transportation of charcoal in the United States, and of these 63 were evidently caused by spontaneous combustion. During 19I I, experiments on the spontaneous heating and ignition of hardwood charcoal were started a t Straight, Pa., and a t Westline, Pa., by the Bureau for the Safe Transportation of Explosives and other Dangerous Articles. The charcoal, after varying treatment as to cooling and air exposure, was loaded into box cars, and the temperature of the interior of these cars was observed a t intervals to detect any increase in temperature. From the incomplete series of experiments performed, i t was reported (Bureau of Explosives, Report No. 5, February, 1912,p. 47) that “no conclusions can be drawn as to the relative efficiency of various periods of cooling and airing. In no case was there any ignition or a n increase of temperature approaching ignition. In every case but one there was a noticeable rise of temperature, which can be ascribed only to the action of air on the cold charcoal, and not to any residual sparks or fire.” The figures obtained so far have not shown t h a t wetting the charcoal increases the heating effects, although it is the general belief t h a t heating more frequently occurs in damp weather. “To attain absolute security from fires of spontaneous origin it is necessary to store the charcoal in the open till such time as i t attains its equilibrium with regard t o absorption of air”-an impracticable procedure, so “the logical alternative is to supplement the best present practice of cooling, airing and storing in open cars for 24 hours prior to shipment by a safe method of ventilation of cars during shipment.” The experiments on the spontaneous combustion of charcoal recently published by the National Physical Laboratory (Report for 1910,85; 1911,86) were conducted in an electrically heated oven, in which I cu. f t . of the charcoal was exposed to a uniform temperature (constant within I C.),measured by
