Experiments and Obfervations. 1 9 
peared to be even fomevvhat nearer to the pot than the above- 
mentioned point. The experiment was then diicontinued, and 
on removing the pot, the needle went back to its original fitua- 
tion, viz. 281°; which fhewed, that its alteration during the 
procefs was occafioned by the aCtion of the acid on the iron, 
and not by any extraneous caufe. 
O11 examination the wire was found only blackened on its fur- 
face, but not nearly confumed ; I had therefore the curiofity of 
trying the fame wire again, and accordingly it was placed in 
the fame veffel near the magnetic needle, which attracted the 
latter from its original fituation 281° to 280°. After adding the 
acid, the needle came nearer, as in the preceding experiment ; 
and a fhort time after it food at 279 0 30b at which time the 
pot was removed, there being no occafion to continue the expe- 
riment any longer. 
On pouring the liquor out of the pot, the wire did not appear 
to be much wafed. The pot was then replaced near the 
needle, fo as to attraCt it a little nearer as before ; but on pour- 
ing boiling water upon the wire, a pretty brifk effervefcence 
took place, and the needle was in confequence attracted fill 
nearer. This experiment (hewed, that though the diluted 
acid had been poured out, yet there remained a quantity of it 
adhering to the wire, which was fufficient to renew the effer- 
vefcence, when aff fed by the heat of the boiling water. 
Upon the whole, it appears, that the aCtion of vitriolic acid 
upon iron or feel increafes their attraction towards the mag- 
net ; that this increafe of attraction has a limit, after which it 
begins to decreale ; and that this limit leems to come fooner 
when iron than when feel is ufedj but, however, in refpeCt 
to this laf particular I am not yet quite certain, fince, in the 
D 2 expe- 
t 
