278 rttvsstc ACID. 



I ftall give a more ample account of this apparatus in a 

 memoir which I (hall prefent to the Inftitute, as foon as the 

 machine which I am now eredling in the country (hall be 

 completed, * 



XV. 



AhJiraSi of a Memoir on the Pojfibiliti/ of obtaining Prufmte of 

 Potajh free from Iron ; the Unalterahility of the Prtiffic Acid 

 at high Temperatures s and the true Nature of the Combina^ 

 tions of this Acid with different BafesA Bj/Bvckolz, 



Utility and ad- J. HE combination of prufTic acid with falefiable bafes, forms' 

 fic"4mpoundV ^ ^^^^^ ^^ ^^'^^ ^^ ^^^ greateft utility to the analytical chemift ; 

 for by means of them he is not only enabled to afcertain 

 whether a metallic fubftance be prefent in any folution which 

 forms the fubjefl of his refearch, but alfo what metal is pre^ 

 fent, as well as its refpedive quantity. But in order to be 

 accurate in this refpedt, the re-agent employed muft itfelf be 

 free from metallic admixture ; or the quantity and nature of 

 / the metal it contains muft at leaft be known. To accomplith 



this, chemifts have hitherto laboured in vain. To remedy 

 thefe defects, Mr. Bucholz has inftituted a number of expe- 

 riments which led to facts hitherto unknown ; and as they are 

 highly important, we (hall exhibit the refults of the principal 

 ones, which are as follows : 



* The pra6llcal mechanic may perhaps find if an advantage to be 

 informed, that the whole effort of a firft mover cannot be tranf- 

 mitted by this, or any other mefhod of raiting weights, in order to 

 operate by their fall. If the wind had been employed to raife a 

 maximum of weight through a given fpace in a given time, this 

 weight would be lefs than would continue in equilibrio at reil againt^ 

 the fame force, as is well known ; and if this weight be again em- 

 ployed in like manner to raife another maximum of weight, this 

 alfo will be lefs than the former, Sec. For this reafon it is that the 

 fly has been ufed as an equalizer of fteam-engines, in preference to 

 the older method of raifing water and fuflfering it to defcend on an 

 overfhot wheel. W.N. 



f Abridged from a memoir in Gehlen's new Journal of Chemifr 

 tfy, yd. I. Part IV. Page 406, by — A. 



1. Pjuflip 



