470 Neii) Scientific Books. [June, 



from reading this letter that I became acquainted with the experi- 

 ment, and have been pursuing it under a variety of forms, and with 

 liquids of different conducting powers, which experiments, when well 

 matured, shall be submitted to your consideration. Would suggest 

 that Mr. W. should repeat the experiment with the water tube. I am 

 disposed to think Mr. W, is in error, when he says the intensity 

 (measured we are to suppose by a pith ball electrometer), indicated 

 was from 10° to 15°. 1 have repeated the experiment several times, 

 but always found a quart jar required an intensity of 65° to 70°; per- 

 haps the pith ball attached to the electrometer was rather large ; it 

 would have been more satisfactory if the degree at which the jar 

 spontaneously discharged itself had also been stated. 



Yours, truly, T. J. 



VI. Volatility of Salts of Strychnia. 



M. Ferrari gives the following process for this purpose : solutions 

 of salts of strychnia slightly acid when exposed to a heat of 212°, so 

 as to be concentrated, then become volatile and the salt evaporates. 

 This property has been remarked in the sulphate, nitrate, muriate, and 

 acetate, and is believed to belong to all the salts. It has been re- 

 marked by M. Collaud and others, that the sulphate of quina is also 

 volatile, and M. Ferrari, on repeating the experiments with the mu- 

 riate and nitrate of quino, found it also to happen with them. The 

 solutions on being heated in a tinned copper vessel, gave out vapours 

 which, when breathed, were found to be highly bitter. The salts vary 

 in the extent of this property, and it is also affected by the degree of 

 acidity, and of concentration of the solution. — (Gior. de Fisica, vi. 

 460.) 



VII. Crystallization of the Sub-carbonate of Potash. 



M. Fabroni describes the following process for the crystallization of 

 this salt. Make a solution of pearlash in water, and evaporate it 

 until of specific gravity 1-57. Allow it to cool, when all extraneous 

 salts will be deposited ; separate the fluid and again concentrate it 

 until of specific grav. above 16. The fluid will now be of a light 

 green colour, and strong alkaline odour ; place it in deep vessels, as 

 glass jars for instance, and the sub-carbonate will soon crystallize in 

 long rhomboidal white laminse, situated vertically and parallel to each 

 other ; one extremity will touch the bottom of the vessel, and the 

 other be attached to a saline crust on the surface of the liquid. When 

 cold the mother liquor will be found of specific grav. 1-6, but if further 

 consecrated and again cooled, more crystals will be obtained ; and 

 thismay be continued until the whole has been crystallized. — (Ibid,45.) 



Article XIV. 

 NEW SCIENTIFIC BOOKS. 



PREPARING FOP. PUBLICATION. 



Mr. Harris Nicolas has in the press, nearly ready for publication, a 

 small w ork intended for the use of Antiquaries, Historians, and the 

 Legal Profession, containing Tables that show exactly the year of our 



