424 Progress in Science. [July, 



a dwelling-house, the floors were taken up, in order to cut off their ingress, if 

 possible. The box that held the hot-water pipes was found to be a favourite 

 resort for the vermin, and had actually been on fire. The sides were charred, 

 but there had not been sufficient air to sustain combustion. Upon investiga- 

 tion as to the cause of the incipient fire, we are not long left in doubt, for a 

 store of remnants of greasy cloths used in washing dishes was found, which had 

 been brought by the rats from the kitchen. Some of these were charred, and 

 the others were well saturated with grease and oil. This fire was a distance from 

 the kitchen range of at least forty feet. It would have been natural in all 

 these cases, if the real causes had not been apparent, to attribute the origin 

 of the fire to incendiarism. The introduction of coal oils for the lubrication 

 of machinery has very materially reduced the number of fires from spontaneous 

 combustion, owing to the fact that the coal oils do not absorb oxygen. 



The employment of the oxyhydrogen blowpipe for attacking safes has 

 recently been the subject of some careful experiments ; the result being that, 

 whilst it is a powerful auxiliary to the drill, it cannot be used alone with 

 success. The temper may be drawn, in time, from a steel plate an inch thick, 

 by the use of the blowpipe, so that the plate may be drilled. It may also be 

 burned quite through when operated upon singly ; but it is difficult to do this 

 with iron plates, which burn less easily, and also conduct heat away from the 

 point against which the flame is directed as rapidly as the steel. Spiegeleisen 

 burns with even less facility than ordinary iron. The flame directed against 

 the corner of a fragment of spiegeleisen fused it, but, after continued action, 

 only produced a comparatively small amount of the oxide of iron, which coated 

 the bead formed. The fused metal, on cooling, was as hard as before. This 

 material, in fact, depends for its hardness upon its natural composition, and not 

 upon any process of tempering, so that mere melting does, not change its cha- 

 racter. It would, however, require apparatus not available to burglars to melt 

 a hole in the centre of a spiegeleisen plate. It follows, therefore, that while 

 iron plates and steel plates may be successively penetrated by the use of the 

 blowpipe, as practically capable of use in the hands of burglars, the spiegeleisen 

 plate, which practically resists drilling, defeats the use of the instrument as an 

 adjunct to the drill. Mr. Dickinson, of New York, manufacturer of carbon 

 points for drills, &c, states that these points will not drill spiegeleisen, except 

 by the use of appliances for obtaining speed, which cannot be used by burglars, 

 and that to drill it at all would be a work of so much time as to prevent its 

 adoption for safe-breaking. The rate at which, by the alternate use of the 

 blowpipe and drill, a hard steel plate can be penetrated, is, according to 

 Mr. Farrell, about one inch per hour; the drawing of the temper in advance of 

 the drill occupying about two-fifths as much time as the drilling. It is found 

 that the alternate use of these instruments enables more rapid progress to be 

 made than when it is attempted to draw the temper entirely through the plate 

 at a single operation. 



A discussion on the subject of the congelation of bisulphide of carbon has 

 been going on, for some time past, in the German chemical journals. 

 Dr. Wartha considers that its congelation, which, according to the treatises on 

 chemistry, requires a temperature of — go° for its solidification, may be easily 

 effected by directing a very rapid current of dry air upon the surface- of the 

 pure liquid contained in a glass vessel. If a thermometer be plunged into the 

 bisulphide of carbon during this operation, a snowy crust will be noticed 

 covering the sides of the vessel and the thermometer, even before the tem- 

 perature has become o°. The temperature then rapidly descends to — 18°, and 

 a white mammellated mass rises to the surface, and sometimes even stops up 

 the tube for conducting the air. Soon all the liquid disappears and the ther- 

 mometer commences to rise again up to — 12 , where it remains stationary as 

 long as the bisulphide of carbon is solid. In this state it presents the same 

 phenomena as solid carbonic acid. Dr. Ballo has verified all the facts stated 

 by Dr. Wartha, but finds that the solid substance obtained is not really solidi- 

 fied sulphide of carbon (frozen sulphide), but is a hydrate of the body alluded 

 to, containing about 19" 14 per cent of water. In a subsequent paper he states 



