PRETENDED NEW METAI.; PALLADIUM. 8^ 



apparatus. When it has been found by experiments^ how 

 much air is extricated from a given quantity of water, running 

 with a known velocity, under a given diminution of prelfure 

 and heat ; the fize and power of the air-pumps may be deter- 

 mined fo as to adt with full advantage, as long as tbefe cir-^ 

 cum(lanc«s remain unvaried. But if they happen to change, 

 the air-pump will either work too much, and expend an un- 

 necetfary force, by extradting water after the air is exhaufted ; 

 or too little, by extracting the air more flowly than it is pro- 

 duced. On the contrary, it feems that the floater, if the 

 yelTels and cocks be of fufficient fize, can never deliver more 

 or lefs than is exa6lly required. 



This confideration, as well as the poffibillty of a conftant but would 

 fupply of water for fmall veflels, without any pumping at all, J^^yy^^^^'^^ ^^'^Jl 

 may in many cafes allow the firft apparatus to be ufed with apparatus, 

 advantage, and even render it preferable, efpecially in elevated 

 jyphons and great rarefadions, as mod commonly occur in 

 pra£lice, when it would not only be very difficulty to keep 

 the air-pump tight without great fridlion, but a quantity of 

 vapour from the heated fluid would be expanded. This in- 

 creafes the difficulty of the air-pump, but in the other con* 

 trivance it is partly condenfed by the cold water in the'ajr- 

 \'eflel trough, which it is obliged to pafs. 



I am with great efteem, My dear Sir, 



Your obedient humble Servant, 

 A. N. EDELCRANTZ. 



II. 



Enquiries concerning the Nature qf a Metallic Subftance lately 



fold in London as a new Metal, under the title of Palladimn, 



, % Richard Chenevjx, Esq. F. R. S. and M.R. I. A.* 



'N the 29th of April I learned, by a printed notice f fent Announce of a 

 to Mr. Knox, that a fubftance, which was announced as a new"^'^"*^'^ ^*' 



metal, 



* From the Phllof. Tranf. 1803. 



i" *' Palladium, or newfilver, has thefe properties among/1 others 

 ** that fhew it to be a new noble metal. 



" l.lt diflblves in pure Ipirit of nitre, and makes a dark-red 



" folution. 2i Green vitriol throws it down in the ftate of a re- 



** gulus from this fojution, as it always does gold frpm a^ua regia, 



; ---- — t,, 0^ jf 



