520 Sir G. C. Haughton on the Common Nahire of 



was withdrawn from the latter, the needle seemed always to 

 set off with more than usual haste, as if strongly repelled, but 

 no symptom of repulsion was exhibited when the ivory was 

 brought near the magnetic needle standing in repose. 



Here was a curious problem to be solved. What was the 

 cause of this extraordinary affinity of a substance like ivory 

 for so many heterogeneous bodies, of which porcelain offered 

 the most remarkable instance,* as the specimen employed, 

 which stood on a surface of glass, drew the ivory as much as 

 one-fourth of an inch after it on one occasion, and always 

 some small distance when it was merely pushed away ? The 

 diamond exhibited the same phaenomenon, but in a minor 

 degree, and careful testing proved that electricity in no way 

 contributed to the results. 



On referring to the tabulated measurements of which I 

 have spoken, and in which the measures of substances stand 

 in ready contrast, I observed that the needles had attached 

 themselves with remarkable facility to animal bodies, sucii as 

 ivory, pearl, mother of pearl, horn, hair, glue, &c. It was 

 evident, therefore, that it was the affinity of something common 

 to all these substances, that caused such easy contact between 

 them and the needles. This step gained it was not difficult 

 to discover that the gelatine which was common to all these 

 animal products, was the substance that chiefly produced with 

 equal facility a contact with gold, diamond, Iceland spar, 

 marble, alabaster, horn, vegetable ivory, gum, and such dis- 

 similar substances, in the mineral, vegetable and animal king- 

 doms. The low attraction afforded by the piece of old ivory 

 of which I have spoken, I suppose to have resulted from partial 

 change in its structure through age ; and the same cause may 

 be assigned for the difference exhibited by the pearl and the 

 mother-of-pearl in their measures, for from the colour and 

 the style of setting of the pearl, less than fifty years could not 

 be assigned for its workmanship, 



I have already alluded to the facility with which all vitreous 

 bodies form connexions, and to include the present class of 

 substances in their proper category, we must get rid a little 

 of our familiar notions, and remember that if gelatine, albumen, 

 gluten, resin, lac and gums are devoted to particular uses 

 that make us only think of them as means of adhesion, they 

 are in fact, when considered under a more extended point of 

 view, animal and vegetable glasses; and what fully establishes 

 this character i^ the extraordinary fact which I have already 

 mentioned, that glue was raised to 38° by contact with a bar- 

 magnet ; but in truth since that portion of this communication 

 was despatched for the press, the piece of glue was raised to 



