16 Mr. Cock on Palladium. 



Loss by experi- 

 ment, per cent. 



D ™?„ ir„; .ra/. 00 :}^ h„ ^ o„ ? ^ ? 



T the rbeca e r. Sed *}<>» H » P* s O,, + 7 HO? 



This sugar, in its relations to alcohol, in the ease and rea- 

 diness with which it crystallizes from an alcoholic solution, 

 and in the appearance of its crystals, has much resemblance 

 to manna-sugar (Mannite). It is more soluble however in 

 boiling alcohol than mannite, and is therefore obtained in 

 larger quantity on the cooling of the alcohol in which it has 

 been dissolved by the aid of heat. Mannite also, if heated 



gradually, may be raised to 300° (I do not know how much 

 igher) without either melting or undergoing any loss of 

 weight. 



Eucalyptus-sugar gives a precipitate of a slightly brownish 

 tinge with caustic baryta ; and a white precipitate is also ob- 

 tained by mixing it with a solution of ammoniacal trisacetate 

 of lead. This salt of lead I am at present preparing for ana- 

 lysis, and I hope to have the honour of submitting the results 

 to the Society at a future meeting. In the mean time the 

 formulas presented in this notice must be considered as open 

 to correction. 



VI. On Palladium — Its Extraction, Alloys, Sec. 

 By William John Cock, Esq.* 



THIS metal was discovered by Dr. Wollaston in the year 

 1803f, as one of the alloys of native platinum, which for 

 some time after this discovery appears to have been consi- 

 dered the only source of palladium ; and as the quantity of the 

 latter metal so alloying the native platinum is very small, it was 

 then considered as a very rare metal : of late years, however, 

 the importation into this country from Brazil of gold dust, 

 alloyed with palladium, has occasioned a much more extensive 

 supply of this metal, as it exists in some specimens of gold 

 dust to the extent of 5 or 6 per cent., and in one instance 

 (that of the gold from the Candonga mine) it constitutes the 

 only alloy of the gold. 



The operation of refining is conducted in the following 

 manner: — The gold dust is fused in charges of about 7 lbs. 



* Communicated by the Chemical Society ; having been read January 

 3, 1843. 



t Dr. Wollaston's original paper on Palladium, reprinted from the 

 Philosophical Transactions, will be found in Phil. Mag. S. 1. vol. xx. 

 p. 163; see also vol. xv. p. 287.— Edit, 



