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POPULAR SCIENCE REVIEW. 
liquid is obtained in the basin saturated with the odorous principles of the 
flowers. — See Les Modules, May 15. 
Gelatinous Silica made into Stalactites. — Mr. E. Thompson (says “ The 
Chemical News”), of the Franklin Institute, U. S. A., in experimenting- 
witb silicate of soda solution, found that when such solution is placed in a 
small porcelain capsule or other suitable vessel, and to it is added about an 
equal volume of concentrated sulphuric acid, taking care not to add to it 
too suddenly, the silica deposited prevents the thorough mixing of the acid 
and silicate. If now the vessel be inclined so as to allow the liquids to run 
as a stream from the vessel, the deposition of the silica takes place in the 
form of an icicle or stalactite depending from the lip of the capsule. On 
close examination, it is found that the acid runs upon the outside of the 
stalactite, whilst the silicate flows down the centre or vice versa, the mass 
growing by successive additions to the lower extremity. The experiment 
is at once both pleasing and instructive. 
A new Detonating Experiment. — Mr. Elihu Thompson has made the 
observation that tin-foil, if wrapped about a few crystals of chlorate of 
potassa, can be made to detonate loudly upon being struck smartly with a 
hammer upon an anvil, or in a mortar. The phenomenon being precisely 
analogous to the well-hnown experiment of triturating sulphur and the 
chlorate. To the best of our knowledge, says the Chemical News,” the 
observation that such metals as tin can be oxidised in this way is a new 
one and worthy of notice. 
The mode of action of Sidphur on Arsenic has been investigated by M. 
Gelis, who has published a paper on the subject, whicb was recently read 
before the French Academy. — The author has obtained the sulphides of 
arsenic by direct action. On heating sulphur with an excess of metal there 
is formed a single product, the bisulphide SgAs. It is red, opaque, and 
crystalline, and is distinct from the false realgar” of commerce. With 
an excess of sulphur we obtain the pentasulphide S^As. If one part arsenic 
is heated in a flask with seven to eight parts of sulphur, the metal dis- 
appears, forming a transparent liquid, which when cooled takes the con- 
sistence of india-rubber ; in time it becomes brittle. Ammonia separates it 
into pentasulphide, which dissolves, and free sulphur. On distillation we 
obtain first sulphur, then sulphur containing arsenic. The pentasulphide 
remains, but it is not stable, for at high temperatures it is resolved into 
sulphur, and a trisulphide SgAs. The sulphide of carbon acting upon the 
arsenical sulphur presents curious phenomena. It abandons at first all the 
common sulphur which it contains, and the liquid becomes coloured. At 
each new treatment it removes a little sulphur without becoming saturated. 
Artificial realgar and orpiment are mixtures of the various sulphides of 
arsenic. 
A mode of fusing Platimmi. — M. Violette,” says the Journal of the 
Franklin Institute,” ‘^communicates the fact that he has succeeded in 
fusing platinum. The draught of the furnace employed was very powerful, 
and the Hessian crucibles employed for the purpose, though lined with 
plumbago, were partially fused. The results of the experiments were as 
follows : — In a crucible of this kind 50 grms. of platinum were placed, 
partly spongy and partly in fragments, and after an hour’s stay in the fur- 
