1 74 On the A^ftatl^s »/ Commerce. 



various acids, and some of their coinbinations witir preci- 

 fiiiable basts. The sulphuric acid pure and unconibined, 

 in my opinion, deserves the preference, as it is found evety 

 where nt a low price, and can be brought ta the same stale 

 of concentration. 



The process which I found to be the most expeditious 

 for judging comparatively rf the value of various speci- 

 mens of alkali, consists in ascertaining how many centiemcs 

 of their weight th«.y reqnire of sulphuric acid for their sa- 

 turation. If this process is not as yet within the reach of 

 s}] buyers, we shall easily find at least persons intelligent 

 enough to execute it well ; for, independently of other che- 

 Tuists, there are apothecaries everywhere who can easily make 

 such trials. 



Description of the Alkali-meter. 



The instrument which I have called the Alkali-metery is a 

 glass tube eight or nine inches long, and seven or eight lines 

 in diameter. It is closed at one end, the other terminated 

 in a kind of small funnel, with a beak a (fig. 3, Plate IV.) 

 adherinj; to the tube by a neck with an aperture of two 

 lines and a half. Upon the shoulder which supports this 

 neck is a hole b, for letting the aif out and in. Fig. 3. is a 

 vertical section of this inslrument mounted upon a stand 

 c, rf, in which it is solidly fixed with mastic, by means 

 of a kind of hook (shown at r, d) left for this pur- 

 pose at the lower extremity of the tube. In order to faci- 

 litaie the carriage of this instrument, it is furnished with a 

 kind of tin case, without a bottotti, having a lid e: the 

 other party, being, like the former, indicated by puncture^ 

 lines, is a tabe open at both ends, and upon which, in 

 order to fasten the lid, there must be a swelling g, g. 



The alkali-meter ought to contain easily 38 eranunes, or 

 76 clenii-grammes, because each division, or degree, which 

 we trace afterwards upon the instrument, represents a demi- 

 giamnie of this liquor, which it is extremely important to 

 proporuon accurately as follows : 



A/kali-metric Liqiior. 

 Take concentrated sulphuric acid, or oil of vitriol of com- 



Dierce, 



