the Attractive Powers of Mineral Acids. 41 
of the quiefeent is 186, and that of the divellent 195, or Ep- 
lom fait, 1 margr. 390. Mem. Par., 1778, p. 339- or alluni y 
1 margr. 387. Ihe determinations, however, with regard 
to allum are not quite fo exact as the foregoing ; becaufe allum, 
whether vitriolic, nitrous, or marine, conftantly retains an 
excels of acid, the exact point of fatu ration cannot be found as 
I have already remarked, and is well known : however, the 
fuperiority is on the fide of the divellent affinities, as it lhould 
be. If, inftead of a folution of nitrous felenite, that of ma- 
rine felenite be mixed with the folutions of the above men- 
tioned vitriolico- neutral falts, the fame fort of double de- 
compofition will happen, and a true felenite will be formed, 1 
margr. 382; and on calculation it will be conftantly found, 
that the fum of the divellent conftantly exceeds that of the 
quiefeent affinities. 
So alio, if a folution of tartar vitriolate be mixed with a 
folution of nitrous or marine Epfom, a double dccompofition 
will take place, though no vifible change will appear in the 
mixed liquor, as vitriolic Epfom is exceeding foluble in water, 
and therefore is not precipitated as felenite is, on account of its 
infolubility, Mem. Par. 1778, p. 338. In the firit cafe, the 
fum of the quiefeent powers is 290, and of the divellent 295 ; 
in the fecond cafe, that of the quiefeent is 2S6, and of the 
divellent 295. 
If a folution of Glauber’s fait be mixed with that of ni- 
trous or marine Epfom, an invifible double decompolition will 
alfo happen, Mem. Par. ibid. Hence Mr. quatremere 
dijon-val, who lately denied this double decompofition (roz. 
Mai 1782, p. 392.) was certainly deceived. In the firft cafe, 
the fum of the quiefeent affinities is 240, and of the divellent 
245 ; in the fecond cafe, that of the quiefeent is 236, and of 
Vol. LXXIII. G the 
