288 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1908. 



were introduced, some being fired in groups by means of pistols and 

 other central-firing arrangements. General Lauer and Mr. Tir- 

 mann introduced friction fuses, which are fired by means of wires 

 from a distance, and are extensively used chiefly in Austrian coal 

 mines. Girard made " cordeaux detonants " by filling lead tubes with 

 nitrohydrocellulose and then drawing them out to the diameter of an 

 ordinary safety fuse. In 1906 these fuses were filled with melinite, 

 and now trinitrotoluene is also used, which permits the employment 

 of lead tubes instead of the costly tin tubes indispensable with a 

 picric acid explosive.*^ The most perfect fuse of this kind is, how- 

 ever, the instantaneous fuse invented by General Hess and introduced 

 into the Austro-Hungarian service. Originally it consisted of a 

 mercuric fulminate core on four threads. In 1903 Hess " phlegma- 

 tized " the fulminate ^ by the addition of 20 per cent of hard paraffin, 

 but a number of such fuses, tied together by knots, can be detonated 

 by a common detonator, thus replacing electric shot firing and dis- 

 pensing with a detonator in each bore hole. The fuse can be cut, 

 hammered, squeezed, etc., without danger. 



The more industry progressed all over the world, the greater the 

 coal consumption became, and the more frequently occurred those 

 appalling mine disasters which from time to time convulse public 

 feeling. The British Government was the first to nominate a fire- 

 damp commission. Then followed commissions in Prussia, France, 

 Saxony, and Austria, but not one of them tried a safety explosive 

 before September, 1885. The Prussian Government, however, had 

 built a testing station and trial gallery at Neunkirchen, in the begin- 

 ning of September, 1885, under the direction of Mr. Margraf. In 

 September, 1887, a carbonite consisting of saltpeter, cellulose, nitro- 

 glycerin, and sulphureted oil was found to be absolutely safe. In 

 188G Margraf tested securite against carbonite, and this also was 

 found safe. In April, 1887, roburite and kinetite were tried, and 

 in August, 1887, soda dynamite. Thus carbonite was really the first 

 safety explosive. 



It is necessary to distinguish between explosives which are safe in 

 manipulation (handhabungssicher) and such that are safe in fire 

 damp (wettersicher). The latter only are called safety explosives in 

 this country. 



The obvious question is, What makes an explosive safe in fire 

 damp ? I confess that, having most carefully examined the views of 

 those most competent to given an opinion, I fail to find a definite 

 answer. At one time the Prussian commission stated that the more 

 rapid the explosion the safer the explosive, and some color is lent to 



« Artilleristische Monatshefte, August, 1908. 



* " Mittbeilungen iiber Gegeustande des Artillerie und Geniewesens," 1907, 

 p. 115. 



