T H E JOCR.VAL OF INDUSTRIAL A N D E S G I S E E R I - Y G C H E J f I S T R Y . Nov., 1 9 1 2

process, especially a t the kiln end, a sheet lead chamber has been introduced a t one works, and has been found a marked improvement. As regards the waste gases resulting from the distillation of ammoniacal liquors, experience continues to show that when using oxide of iron purifiers, the heap form is to be preferred, and that the low broad-based heap has advantages over the high conical heap with comparatively restricted base.

A further installation for the manufacture of -bleaching powder in a mechanically wrought plant was put into operation during the year, and is favorably noticed as minimizing nuisance from dust, escape of chlorine, etc. In view of the present over-pro- duction of the carbide industry, the attention of manufacturers is drawn to a possible new outlet for chlorine in the preparation of a series of compounds starting from the parent substance acetylene tetrachloride. (In the United States manufacturers are making inquiries concerning a commercial process for making hydrochloric acid from chlorine and hydrogen; and the possible commercial production of chlorine substitution products of methane occurring in natural gas is under investigation.) I t is reported that the employment of coke towers in the production of chlorine for bleach manufacture is being given up in certain English districts, as they lead to reactions taking place which are detrimental to the formation of high-class bleach.

SULPHUR DIOXIDE FROM IRON PYRITES. -4 Mechanicsville, N. Y., paper concern, which uses large

quantities of sulphur dioxide in its sulphite plant in the manu- facture of sulphite fiber, is contemplating the erection of a plant for the production of sulphur dioxide from iron pyrites. The ore is to be obtained from Pyrites, Canada, and will be trans- ported to Mechanicsville by barges; after treatment, the iron ore will be sold to iron furnaces. The obtainment of sulphur dioxide by the proposed plan is new in New I‘ork, but has been in use in Virginia for several years. I t is reported that sulphur dioxide can be produced from pyrites for use in paper mills a t a much less cost than it can be obtained by burning native sulphur.

A HYDROGEN-SUPPLY FOR DIRIGIBLE BALLOONS. The “Elektron” works of the Chemische Fabrik Griesheim

have laid a line of hydrogen supply pipes from their works to the airship-harbor at Frankfort-on-;Main. This line has a length of z3/, miles and is laid much in the same way as gas pipes. Most of the joints are, however, welded, in order to avoid risks of escape of the gas, and sleeve couplings are used in only a few places. The hydrogen is obtained as a by-product in the electrolytic production of sodium hydroxide and chlorine. At the present time about 1,000 cubic meters of hydrogen can be supplied daily under a head of I ,000 mm. of water. A hydrogen gas-holder of 6,000 cubic meters capacity has been constructed near the hangar, with which it is connected by several distribut- ing pipe lines.

“DUROBAX” GLASS. The Jena glass works have introduced several special glasses

for water-gauges. In 1891, this firm marketed “robax” glass; in 1900, “durax” glass; and quite recently “durobax” glass (Eng., 94, 330) . Nearly all glasses for water-gauges can stand a pressure of 200-300 atmospheres in the cold. Exposed to the action of superheated steam, all glasses will likewise fail a t pressures of about 35-40 atmospheres, as the tensile strength of glass falls off very much a t about 250’ C. This may be de- termined in the Schott and Herschkowitsch apparatus, which also serves for the determination of the pressure a t which a glass under high pressure and temperature will fail when sud- denly played upon by a jet of cold water. This apparatus consists of a strong iron pipe, bent to a loop, and provided with sockets and glands for fixing a water-gauge a t the ends; the pipe is further fitted with a pressure-gauge, a valve, and a cock for

filling it with water. The whole apparatus is placed in a box and heated by a Fletcher burner. In front of the box is a small glass tube, through which cold water is kept flowing; this jet of water can, by turning the tube, be so directed that it strikes upon the water-gauge. This cold jet is repeated a t pressure intervals of z atmospheres until the gauge cracks. Ordinary gauge glass will, under this treatment, stand only 6-7 atmos- pheres; “robax” glass will stand 15 atmospheres; “durax” glass, 2 7 atmospheres; while “durobax” glass breaks only a t a pres- sure of 31 atmospheres. Thus the limit of resistance would in this respect almost be reached, for a t a pressure of 40 atmos- pheres the glass would fail simply owing to thermal stress. The resistance to water-sof tening agents was deduced from the loss in weight which the glass showed when kept for 24 hours in steam a t 8 atmospheres ( 1 7 1 ~ C.) in solutions of sodium carbonate and sodium hydroxide (0. j per cent.). “Durobax” glass lost 1.5 and 3.09 mg. per sq. cm. The loss in good feed water was I mg. in 31 days.

- “TRIPLEX” GLASS.

“Triplex” glass, a French product, is said to be a perfectly transparent sheet or plate, which, when broken, does not fly into pieces, and which may be cracked but not smashed to bits. I t is made as follows (La Kalctre, August 17, 1912): Two sheets of glass are taken and one face of each is covered with a thin layer of gelatin; the sheets, gelatin faces opposite, are placed together, with a very thin sheet of celluloid interposed. The whole is then subjected to hydraulic pressure to render the combination solid. Ordinary sheets of glass are shattered t o fragments by a mass of two pounds falling 10-12 feet. “Tri- plex” glass is cracked, but it resists the shock and the pieces are not separated; the energy of the ball is absorbed in a much greater number of fractures, but the pieces remain adherent be- cause of the layers of gelatin between them. Such glass may be of great service in carriages, automobiles, public conveyances, etc., and the invention should be of considerable interest to accident insurance companies.

IMPORTS AND EXPORTS OF CHEMICALS. The imports and exports of chemicals and fertilizers, including

raw materials for chemical manufactures, in the United States for the seven months ended July 31, 1912, follow. Exports include re-exports of foreign materials.

Imports. Exports. Cofifier sulphate in pounds.. , , . , . . . . . . . 5,504,879 Bleach in pounds., . . , . . . . . , , . , . . . 400 Potash salfs in pounds. . . . . , . . . . . 1,710,625 Soda salts in pounds, . . . . . , , . . . . . . 300,808 Acetate of lime in pounds.. . . . . . . . . . . . . 45,777,383 Phosphates in tons.. . . . . . . . . . . . . . . . . . . 702,767 Sulphur in tons.. . . . . . . . . . . . . . . . . 24 944

,Magnesite in pounds.. . , . , . , , , , , . . 1,333,024 Ammonium sulphafe in pounds. . . . 56,560,924 357,600

850

41,520,981 374,784,300 7 I 187 I 205

15,377

128,756,843 Pyrites in tons.. . . . . . . . . . . . , . . . . . 555,059 . . . .

Arsenu in pounds.. . , . . . . . . , , , . . . 2,983,425

ACID-RESISTING ALLOYS. I t is reported that Borchers has produced alloys of iron which

will resist entirely the action of acids, while the articles produced can be manipulated by the usual workshop methods. The new alloys are prepared by adding from 2 to j per cent. of molybde- num to an alloy of ferrochrome, which contains no carbon or very little, and not less than IO per cent. of chromium. An alloy which contained only 36 per cent. of iron, against 60 per cent. of chromium, was found to be insoluble even in boiling nitric acid, while it possessed all the usual qualities of iron and could be worked in the usual way. Not quite such favorable results were obtained by adding titanium and vanadium.

I t is claimed in Metal Industry, Aug. 12, 1912, that if bismuth