436 



The faces of the form 1 are large and bright ; those of all the 

 other forms are extremely narrow, and are usually uneven. 



Cleavage 001, very perfect. 



No other forms of crystals than those just described were observed 

 in any of the alloys experimented with. 



The largest and best-defined crystals were obtained from the alloys 

 containing about 41 per cent, of gold. The plates were sometimes, 

 when crystallized from 300 grms., about 30 millims. long and 15 

 millims. wide, being the height and depth of the alloy in the 

 crucible ; they were generally of a bronze colour, proceeding from a 

 slight oxidation of the tin : their true colour was that of tin. All 

 the alloys emit a grating sound when cut through, as tin does, and 

 are all exceedingly brittle. 



From the above experiments it appears, first, that the well- 

 defined crystals are not limited to one definite proportion of the con- 

 stituents of the alloy, but are common to all gold-tin alloys con- 

 taining from 43 to 27*4 per cent, gold; secondly, that crystals and 

 mother-liquor are never of the same composition. These facts coin- 

 cide with those found by Cooke* in his research on tin and anti- 

 mony alloys, who observed that zinc and antimony are capable of 

 uniting and producing definite crystalline forms in other proportions 

 than those of their chemical equivalents. 



X. "On the Sensory, Motory, and Vaso-Motory Symptoms 

 resulting from the Refrigeration of the Ulnar Nerve." By 

 AUGUSTUS WALLER, M.D., F.R.S. Received September 3, 

 1861. 



In a brief account of the effects of compression of the human 

 vagus and sympathetic nerves f, I mentioned as one of the symptoms 

 produced, " a tingling and heat of the ear corresponding to the side 

 compressed, often lasting upwards of half an hour after removal of the 

 pressure." 



The sensations thus experienced are frequently of a hot, mordicant 

 character, as if arising from the passage of a hot fluid through the 

 vessels, extending progressively and causing a flush over the surface 



* Silliman's American Journal, (2) vol. xx. p. 222. 

 t Proceedings of the Royal Society, No. 44, page 302. 



