XIV. Continuation of the Experiments and Obfervations on the 
Specific Gravities and Attractive Powers of various Saline 
Subfiances . By Richard Kirwan, Efq . F . R. S, 
Read April n, 1782. 
B efore i enter into a detail of the new experiments I 
have made in the profecution of this fubjeCt, I mull beg 
leave to rectify fome miflakes I have fallen into in my lafl 
paper. 
1. In computing the quantity of acid taken up by 10,5 gr. of 
mild vegetable fixed alkali, I made no allowance for the fmall 
quantity of earth it contains, viz . 0,70 35 of a grain ; but in 
large quantities of alkali, this proportion is conliderable, and 
occalioned a fmall but fenlible error in my fubfequent calcula- 
tions of the proportion of ingredients in neutral falts, the 
quantity of alkali being, bv that fraction, lefs than I fuppofed 
it in 10,5 gr. This correction being made, it will be found, 
that 100 gr. of perfectly dry vegetable fixed alkali (abftraCted 
from the quantity of earth) generally contain 22,457 g r - °f 
fixed air inftead of 21, as I before determined ; yet the former 
determination is right, where the earth is not feparated, yet 
may well be fuppofed to exift, as in the alkali of pearl-afh, 
purified by three repeated calcinations and folutions. Hence 
alfo 100 gr. of fuch alkali, free from earth, water, and fixed air, 
take up 46,77 gr. of the mineral acids, that is, of the mere 
A a 2 acid 
