Dr. Marcet’s experiments and researches, &c. 44$ 
in sea salt :* and I saw soon after in the ‘ Annales du Musee ,' 
Vol. VII. a paper by the celebrated chemist Proust, who, in 
a great measure, confirmed that statement, by announcing 
that he had found traces of mercury in all the specimens of 
marine acid which he had examined. 
Improbable as the fact appeared, I thought it worth while 
to repeat the experiment, and to take that opportunity of 
making some collateral researches upon other substances, 
much more likely than mercury to be discovered in sea 
water. 
For this purpose I availed myself of the kindness of my 
friend Mr. John Barry, ■ f who happened to be in the vicinity 
of Portsmouth, to supply me with specimens of sea-water, 
carefully concentrated upon the spot, in vessels of Wedgwood 
ware, and with scrupulous attention to cleanliness in the pro- 
cess. Accordingly he was so obliging, as not only to send 
me a quantity of brine evaporated under his own eye, in the 
manner just mentioned, but he also collected for me a valu- 
able series of specimens from the salt works near Portsmouth, 
from all the stages of the process, so as to afford me an 
opportunity of investigating with accuracy, all the chemical 
circumstances of this interesting branch of national oeconomy. 
Finding myself, however, much pressed by time at this late 
period of the session, I shall, after briefly adverting to 
Rouelle’s supposed discovery, confine myself in this com- 
munication to a few observations which I have made on sea- 
water itself ; keeping out of view, for the present, the topic 
* See c Journal de Medecine,’ Vol. xlviii. 1 777, page 322. 
f Mr. John Barry, of Plough Court, inventor of a new and valuable process 
for preparing extracts in vacuo, &c. 
3 m 
MDCCCXXII. 
