On the Products of the Distillation of Benzoate of Copper. 3 



Chloride of silver. 



lead. 

 Protoxide of arsenic. 



antimony, 

 lead. 

 Oxide of bismuth. 

 .,. tin (native). 



manganese (native). 



Sulphuret of copper. 



iron. 



lead. 



silver. 



tin. 

 Carbonate of iron, native. 

 Prussian blue. 



Crystallized sulphate of iron. 

 Calomel. 



Thus it appears that only iron, nickel and cobalt are mag- 

 netic, or can be made magnetic amongst metals after the man- 

 ner of iron; but the addition of cobalt, and still more, the 

 very high temperature required to take away this property 

 from it, increases the probability* that all the metals form a 

 common class in respect of this property; and that it is only 

 a difference of temperature which distinguishes these three 

 from the rest, just as it also in a similar respect distinguishes 

 them from each other. 



In connexion with the effect of heat it may be remarked 

 (and perhaps has been remarked already), that, assuming an 

 elevated temperature for the internal parts of the earth, then 

 it is evident that at a very moderate distance from the surface, 

 as compared with the earth's tliameter, the substances compo- 

 sing the earth must be destitute of such magnetic power as is 

 possessed by a magnet; and, at a distance somewhat greater, 

 none of them can retain even that power which soft iron has of 

 becoming magnetic by induction. In such case, whether the 

 earth be considered as magnetic of itself, like a loadstone, or 

 rendered magnetic by induction under the influence of exter- 

 nal magnetic masses, as the sun for instance ; still it can only 

 be in its crust that the magnetic power could be developed. 

 Assuming with Ampere, that the magnetism of the earth is 

 due to electric currents circulating around it parallel to the 

 equator, then of coui'se the above observations regarding the 

 effects of heat would not apply. 

 Royal Institution, June 7, 1845. 



II. On the Products of the Distillation of Benzoate of Copper, 

 By John Stenhouse, Ph,D.\ 



EAR the conclusioHrol^ Dr. Ettling's very able and ela- 

 borate paper on the- Essential Oil of Spirea Ulmaria 

 and Salicylous Acid, which appeared in Liebig's Amialen for 

 1840, it is shortly stated, lhat^5y the destructive distillation of 



» Phil. Mag., 1836, vol. viii. p. 177. 

 'I' Communicated by the Author. 

 B2 



N 



