Liquid air as an explosive

Liquid air as an explosive

298 N o t e s a~zd Comments. [J. F. I., Mexico, Socidt6 G6ologique du Nord, France, Soci6t6 G6ologique de Belgique, Belgium, Military Order of the ...

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298

N o t e s a~zd Comments.

[J. F. I.,

Mexico, Socidt6 G6ologique du Nord, France, Soci6t6 G6ologique de Belgique, Belgium, Military Order of the Loyal Legion of the U n i t e d S t a t e s N a v a l V e t e r a n A s s o c i a t i o n ; C i n c i n n a t i S o c i e t y in New jersey ; Penn,~vlvania Society of the Sons of the Revolution ; m e m b e r a n d V i c e - P r e s i d e n t o f t h e S o c i e t v o f t h e W a r o f it812; m e m b e r o f t h e S o c i e t y o f C o l o n i a l W a r s in P e n n s y l v a n i a , S o c i e t y o f A m e r i c a n A u t h o r s ; life f e l l o w o f t h e A m e r i c a n A s s o c i a t i o n f o r t h e A d v a n c e m e n t o f S c i e n c e , a n d G e o l o g i c a l S o c i e t y of America. Officier d e l ' I n s t r u c t i o n P u b l i q u e , F r a n c e ; a n d c o r r e spondent der Reichsanstalt of Austria. He received from the City o f P h i l a d e l p h i a on r e c o m m e n d a t i o n o f t h e F r a n k l i n I n s t i t u t e , t h e J o h n S c o t t L e g a c y M e d a l f o r a c o l o r i m e t e r in 19o6. H e is a member of the Board of Managers of the Franklin Institute.

L I Q U I D A I R AS AN E X P L O S I V E . A few notes o n the use of liquid air as an explosive are given in the Montan-Zeitu~lg (May 15, I9O7). The substance was first used only in combination with others. It is now used alone, its explosive power depending upon its property of turning suddenly into vapor at an elevated temperature. If the vessel in which the liquid air is conta.ined is sufficiently tight, very high expansive powers are attained. For this reason it is stored in vessels having a small opening. This property of the liquid air makes it necessary to place the cartridge in place in the rock before it is loaded. In English mines the cartridges are made of thick phosphor-bronze, the loading being calculated so that the pressure reaches 5.6 kg. per sq.cm. The explosion takes place in six or eight minutes after loading and about thirty tons of coal are broken by one shot. The coal falls in blocks about 6o cm. in circumference. A heavier loading of the cartridge causes the coal to be broken into powder.--Eng, and Min. Jour. S U L P H U R I C A C I D M A N U F A C T U R E IN GREAT B R I T A I N . In Great Britain sulphuric acid is .made almost entirely from pyrites, imported chiefly from Spain. Brimstone is used less every year, and is reserved for the manufacture of acid for very special purposes. Sulphereted hydrogen derived from the waste gases of sulphate of ammonia manufacture has been applied extensively during recent years and is an important source of supply of sulphur. British producers of sulphuric acid complain of the increasing difficulty of obtaining pyrites free from or low in arsenic, and several new plants for de-arsenication have had to be erected. The process now used by the United Alkali Company for removing arsenic produces it as pure arsenious acid, instead of the mixed mud of arsenious sulphide as formerly. It is interesting to note that in the midland counties of England "coal brasses" from the coal mines are used as a source of sulphur at the sulphuric acid works.--Eng, and Min. Jour.