72 Malkalk P latins. 



vatioiis on tlie tnu-cito of the living hiiniaii body during surgical 

 operations — on muscles of litnhs immediately after amputation — 

 and on the muscles of some of the lower animals. 'Ihe residt is, 

 that the muscular fibre during its contraction does not exhibit 

 any appearance of rugae, but remains straight ; and is not per- 

 ceptibly enlarged in its transverse diameter. 



A criticism, bv Mr. Mackenzie, on the tragedy of Bertram. — 

 A memoir, bv Mr. Alison, on the Life and Writings of the late 

 Lord Woodhouselee ; — a paper, by Mr. Cadel, on the lines that 

 divide each semi-diurnal arc into six equal parts ; — a paper, by 

 Dr. Jackson, containing an elementary demonstration of the 

 composition of pressures; — additional remarks by Dr. Murray 

 on a lamp for illuminating coal mines; — and a proposal, by Mr. 

 Kennedv, to introduce a bell-shaped bulb of glass, attached to 

 a spiral spring fastened to the top of the barometer tube, to 

 render the instrument less liable to damage by the concussion of 

 the mercury. 



XX. Intelligence and MiiceUancoiis Arl'ulcs. 



JVfALLUABI.K FLATINA. 



Xn the Journal of Science and Art, published at Florence, the 

 Marquis Ridolfi has given a now process for purifvii^g platina. 

 Having observed the fact that no person had been able to com- 

 bine sulphur with platina, he conceived the idea that, by con- 

 verting all the other metals found in crude platina into sulphn- 

 rets, it would be casv to purify that metal. His process is very 

 simple. He first separates from the crude platina some of the 

 extraneous substances usually mixed with it, and washes the re- 

 mainder .with nitro-muriatic acid diluted with four times its 

 weight of vyater. He then melts it with half its weight of pure 

 lead, throws it into cold water, and thus obtains an alloy, which 

 lie pulverizes, mixes with an equal portion of sulphur, and throws 

 into a white-hot Hessian crucible ; covers the crucible instantly, 

 and keeps it in an intense heat for ten minutes. When cold, a 

 brittle metallic button, composed of platina, lead and sulphur, i> 

 found beneath the scoria. This button he fuses v.ith a small 

 addition of lead: the sulphur separates itself with fresh scoria, 

 and there remains only an alloy of pl;itina and lead. This alloy 

 he heats to whiteness, and in that state beats it with a hot ham- 

 mer on a hot anvil, which forces out the lead in fusion. If the 

 alloy be not at a white heat when beat, it will break. The pla- 

 tina thus obtained is ductile, malleable, and as tenacious as that 

 obtained froin the amrnoniucal muriate, He was able to make 



wive 



