Magnetisjn, Cohesion^ Adhesion and Viscosity. 457 



Amongst the animal products, pearl and mother-of-pearl 

 are conspicuous in this class for tiieir attraction for the mao-- 

 netic needle, and for gold, copper, brass, lead, platinum, zin*c, 

 tin, and in all probability for the other metals, though they 

 were not tried. Glass attracts it with equal facility. Horn 

 of all kinds is extremely magnetic. The hair of the head has 

 been already alluded to, and it must excite surprise that a 

 body so fine could contain such high magnetic properties ; 

 and the fact is of extreme use as proving the very circum- 

 scribed extent of the spot, or rather of the point, which is 

 connected with the needle in these experiments, for the very 

 finest hair of the head that can be found exhibits as strong an 

 affinity as the thickest of the same kind. Amongst hair^the 

 white whisker of a cat, of the mixed Angora breed, must not 

 be omitted, as it was distinguished above all for its attractive 

 properties which it maintained for all the substances with 

 which it was tested. 



Jet. 



Sepia 24 



Indian ink 70 



Amber 75 



Resin 90 



Bee's wax. 



Qth Class. 



Spermaceti. 

 Composition candle. 



Lac (pure) 35 



Do. (red) 17 



Do. (yellow). 

 Sealing-wax (red) 36 



Sealing-wax (black) 25 



India rubber 80 



Gas coal 15 



Pit coal 



Charcoal (of commerce) 



Do. (box) 



The substances of this class show no remarkable attraction 

 for the magnetic needle, but this is not surprising when their 

 nature is considered. 



Deal wood .30 



Box wood. 

 Rose wood. 



J'oplar 52 



Oak. 



Lignum vitae 33 



Beech. 



Walnut wood 



Mahogany. 



7i/i Class. 



Cane* (outside). 

 Do. (inside). 

 Wheat straw. 



Plain card 80 



Polished card. 



Cedar wood 



Sandal wood 



Cork 



Vegetable ivory 56 



* Calamus rotany, 



Vegetable ivory (2nd speci- 

 men) 



Do. (3rd specimen) 



Glue 29 



Dry paste on paper 



Letter paper (thin French). 



Do. (thin English) 



Do. blue laid (hot pressed) 



Do. thin Bath (hot pressed) 



The woods, as might be expected, did not exhibit much 

 attraction for the needle; but I shall have to .speak of them 

 again when I treat of the magnetism of non-lerru^inous 

 bodies, to which I now proceed. ° 



[Continued at page 502.] 



