35 
a sudden transition of the atmosphere, either from a rarified to a 
dense, or from a dense to a rarified state. 
The honour which the Royal Society proposed to confer upon 
Dr. Brownrigg, by inserting these essays in their Philosophical 
Transactions, was declined by him, as it was his intention to 
publish them on some future occasion, enlarged and improved by 
many additions and corrections. 
Desirous also that his observations should be confirmed not 
only by his own experiments, but by the attestation of others, he 
solicited and received the opinions of many of his literary friends, 
particularly of Sir Hans Sloan and Dr. Hales. Furnished with 
necessary materials, and qualified for the execution of so difficult 
a task by his indefatigable perseverance and his attachment to 
chemical philosophy, he long had it in agitation to write a general 
history of fire damps. With this motive, he retired from his 
professional avocations to his paternal seat, Ormathwaite. The 
outlines of his history of damps having been sent to Dr. Hales for 
his private perusal, were submitted by that celebrated philosopher 
to the inspection of the Royal Society ; but, notwithstanding the 
importunities of those who were able to appreciate their merits, he 
could never be prevailed upon to give his consent to their public- 
ation. An incontestable argument, however, of his attention to 
_ the properties of damps, and the deference which was paid to his 
judgment, arises from his being frequently consulted when an 
explosion in mines was apprehended. By observing the degree of 
rapidity with which the mercury descended in the barometer, he 
_ could foretell the exact period of an explosion; and his predictions 
~ were too often verified by some melancholy event. 
The only work which he permitted to be published on the 
subject of damps was, “An Extract of an Essay on the Uses of a 
_ Knowledge of Mineral Exhalations, when applied to discover the 
_ principles and properties of mineral waters, the nature of burning 
fountains, and those poisonous lakes called Averni.” This ingenious 
_ tract was read before the Royal Society in April, 1741. The 
_ object of it is to prove that the distinguishing qualities of mineral 
_ waters depend on a particular kind of air which forms a consider- 
