32S Dr. Pearson’s Experiments and Obfervations 
( e ) Pruffianated foffil alkali occafioned a very flight opal 
coloured appearance, and after (landing fix days a very fmall 
quantity of vvhitifli fediment was thrown down, which dif- 
folved on concentrated acetous acid being added, and the liquid 
turned greenifh; but, after (landing, a little greenilh fedim nt 
was depofited, not, however, apparently more than was produced 
by a mixture of this Pruffian alkali, acetous acid, and water. 
(/) Phofphorated foffil alkali produced no turbidnds or 
precipitation on ftanding a week 5 but on the addition of 
gr. of nitrated mercury (which had been made by fully 
faturating the nitrous acid with mercury) the mixture grew 
inftantly thick, and depofited a copious white fediment. 
3’dly, The remainder of the refiduum, in the retort 
above mentioned to have been left after diddling to dry- 
nefs acetous acid in which James’s Powder had been boiled, 
did not totally diffolve in a large proportion of nitrous acid 
diluted ; but was wholly taken up on adding a little marine 
acid. A great part of the fuperabundant acid of this folution 
being x carried off by evaporation, it was examined with the 
following fubflances. 
(d) Adding a little of it to a large proportion of water, 
milkinefs enfued. 
(i) The fame appearance took place with a large proportion 
of lime-water. 
(c) A turbid bluifh colour was produced on adding Pruffian 
mineral alkali, and on handing a bluifh fediment took place. 
(d) A poiiffied copper plate was not at all whitened by im- 
merfion in this folution; but, on adding to it of a grain 
of nitre of mercury, the copper was rendered paler coloured. 
The deficiency of twenty grains of powder in thefe 
.experiments with acetous acid muff be afcribed partly to the 
,, folution 
