CHEMICAL SCIENCE. 247 



trary, has no effect whatever upon the action of these poisons. He 

 also believes that animal charcoal neutralizes the stupefying action of 

 the vegetable alkaloids, as quinine, strychnine, and morphine. 



Chemical Preservation of Statues. M. Dalemagne, in a recent 

 communication to the French Academy, is of the opinion, that coating 

 statues, exposed to the atmosphere, with a solution of silica, is quite 

 sufficient to insure their preservation. In proof of this, he calls 

 attention to the circumstance that certain busts which were submitted 

 to the process of silicatization ten years ago, are now in a state of 

 perfect preservation; while others of the same age, placed under the 

 ordinary conditions of the atmosphere, and even to which consider- 

 able attention had been paid, are now in a state of more or less marked 



decay. 



******** 



Kuhlmann on the Coloring Material in Minerals. In the course of 

 his new researches on the preservation of materials employed in 

 building and ornamentation, this able investigator has availed himself 

 of the new methods of analysis by the spectrum, with modifications. 

 He expresses his belief that he has placed in the hands of chemists a 

 sure, simple, expeditious, and safe method of analyzing the largest 

 part of the silicious stones and a great number of natural and artificial 

 silicates ; and that he has put investigators in the right way of finding 

 out the true cause of the color of certain stones ; and finally, that he 

 has opened up a new field of research in spectral experimentation, in 

 analyzing by the gaseous way those minerals whose character so much 

 depends on the nature of the solvent engaged in their formation. 



Coloring Matter of the Emerald. -M. Lewy in 1858 asserted that 

 the coloring matter of the emerald was organic and destroyed by heat. 

 Recent researches by M. M. Wo'hler and Rose seem to show, how- 

 ever, that the color is due to oxyd of chromium. They kept an em- 

 erald at the temperature of melted copper for an hour, and found that, 

 although the stone became opaque, the color was not affected. They 

 fused, however, some colorless glass with an exceedingly small quan- 

 tity of oxyd of chromium, and produced a color exactly like that of 

 the emerald. They therefore considered this substance the coloring 

 agent, without, however, denying the presence of some organic 

 matter. 



A new Method of Extracting Gold from Auriferous Quartz, so 

 as to obviate the necessity of employing mercury, which is both ex- 

 pensive and very deleterious, -has been suggested by Prof. Grace 

 Calvert. Finding that gold, though but slowly acted on by a solu- 

 tion of chlorine, is readily dissolved by that agent as it is liberated 

 from its other combinations, or as in a nascent state, Mr. Calvert sug- 

 gests that the auriferous quartz should be acted on by hydrochloi'ino 

 and peroxide of manganese, when the gold is readily and completely 

 dissolved, and is, after the separation of any copper that may be 

 present, afterwards precipitated in a metallic form by a solution of 

 protosulphate of iron (the green copperas of commerce) . 



New Method of Detecting Poisons in the Animal Economy. Dr. 

 Machaltee, in a paper presented to the British Association on the use 

 of the new process of dialysis for the detection of poisons, suggested 

 that the stomach or intestines of an animal suspected of having been 



