Dr . blagden’s Eifory of 
ferted in the Philofophical Tranfadtions *, that it would be 
improper for me to dwell upon any further particulars. I will 
only obferve, that though many of the circumftances men- 
tioned by M. braun were not firft remarked by hrmfelf, yet the 
difl'ertation is compofed entirely in his name, all the other gen- 
tlemen very generoufly giving up their part to him who made 
the original difeovery, and undertook to put the whole in a 
fit drefs to appear before the world. 
Five years afterwards, Profeflor braun again addrefled the 
publick on the fame fubject, under the title of “ Supplements” 
to his former difl'ertation t* Here he declares, that fince the 
firft difeovery he has buffered no winter to elapfe without 
making fimilar experiments, and never failed of fuccefs in 
freezing the quickfilver, whenever there was a proper degree of 
natural cold, which he ffates at - io°, in order for the experi- 
ment to be complete, though fome commencement of conge- 
lation might be perceived when the temperature of the air is as 
high as 4- 2 °. He confirms all his former obfervations, and 
adds many others to illuftrate them ; among which two are 
very important, as coming nearer than any yet known to afeer- 
tain the real contraction that quickfilver buffers in becoming 
fojid. At the fame time it muff; be confefled, he has not 
rectified any of his former miffakes : he retains the fame 
groundlefs opinions relative to the freezing point of the quick- 
filver, the prodigious cold generated by his mixtures, and the 
explanation of various phenomena, which depend upon very 
different principles, from thole to which he afligns them. 
* Vol. LII. P . 156. 
f Supplementa de Congclntione Mercnrii. Nov. Comment, Acad. Scient. 
Imperial. Petropol. tom. XI, p. 302. 3c feqq. 
The 
