Formation of nitrous Acid. 273 
as from the alkali not being fatu rated. I am much inclined to 
think, therefore, that, fo far from the foap-lees not having 
been faturated, the quantity of acid produced was in reality- 
much more than fufficient for tins purpofe, and had diflolved 
/ 
a good deal of the mercury ■, for the quantity of air abforbed 
favours this opinion, and the phenomena agree well with Mr. 
Gilpin’s firft experiment, in which this was certainly the 
caie ; whereas, if the diminution had proceeded chiefly from 
the dephlogiflicated air being abforbed by the iron, the tube 
towards the end of the experiment would have been filled 
chiefly with phlogifricated air, which would have made the 
diminution proceed much flower than before; but we are told, 
that it went on as fall as ever. It is mofl likely, therefore, 
that the apparent difagreement between their experiment and 
mine proceeded only from their having continued the procefs 
too long, and from their not having properly examined the 
produce. 
M. Van Marum then proceeds to fay ; 44 Surpris de cette 
44 difference de refultat j’envoyai une defcription exa£!e de nos 
“ experiences aM. Cavendish, le prianten meme terns dem’in- 
44 ftruire s’il pourroit trouver la caufe de cette difference ; et 
44 comme la feule difference eflentielle, par laquelle notre expe- 
44 rience differoit de celle de M. Cavendish, confifloit en ce que 
44 nous avons employe de fair pur produit du precipite rouge ou 
44 du minium, au lieu de l’air pur produit de la poudre noire 
44 formee par l’agitation du mercure avec le plomb, dont M. 
64 Cavendish ne donne pas la maniere de le produire*, je le 
44 pria^. 
* The ufmg the iron wire formed a material difference in our manner of 
conducing the experiment, and one which may, perhaps, have had great 
influence on the refult $ but I do not fee how the uflng fome other kind of 
dephlo- 
