492 Rev. W. V. Harcourt on Lord Brougham's statements, 



placed the egg under water, where it exploded. Fludd also 

 burnt a candle in a glass vessel over water, and observed that 

 it raised the water in proportion to the quantity of air, en- 

 closed in the vessel, which was consumed and burnt; for 

 "air," he adds, " nourishes fire, and in nourishing consumes 

 it." This sounds like the truth which Hook announced : but 

 Fludd had no distinct idea of the weight of air, or of the great 

 principle which led that philosopher to predict, and observe, 

 ponderable products from its consumption. 



Boyle supported Hook's views by "affirming that gun- 

 powder burns very well in a receiver out of which the air has 

 been extracted," and he afterwards took the pains to experi- 

 ment with nitre compounded of nitric acid and potash out of 

 contact with the atmosphere "m vacuo Boyleano," for the 

 sake of " removing the suspicion that it does not burn without 

 air being supplied by the numerous eruptions of the aerial 

 particles intercepted, by those that by their coalition make up 

 the nitrous corpuscles*." Boyle also remarked at this discus- 

 sion that "tin mixed with nitre will kindle it;" to which 

 Hook added, that filings of iron will do the same. This re- 

 mark was justly deemed of such importance, that the Society 

 ordered the experiment to be tried ; and it was found that 

 " filings of tin being cast on nitre, over a fire, made it flame ; 

 though it benot known," adds thewriter of the Minutest, "that 

 sulphur was ever extracted out of tin ; which seems to infer 

 that there are bodies combustible which are not sulphureous" 



The only verification, in the Registty, of the intimation 

 given in the Micrographia that the same principle in the air 

 which supports combustion is concerned "in respiration and 

 the preservation of life," consists in an experiment suggested 

 by Dr. Ent, in which a bird was enclosed with a chaffer of 

 live coals in a receiver ; the Society observed the extinction 

 of the fire to be followed by failure of vitality in the bird, which 

 revived on the readmission of air. 



After these inquiries Dr. Wilkins proposed (on the 8th of 

 March 1764) "that the following experiment (of Dr. Wren's 

 suggestion) might be made, viz. to put a fermenting liquor in 

 a glass ball to which a stop-cock should be fitted, and to tie a 

 bladder about the top of the stop-cock, by which means a 

 certain air generated by the fermenting liquor would pass into 

 the bladder, and upon the turning of the stop-cock be kept 

 there in the form of air without relapsing into water. This, 

 or the like, to be tried at the next meeting. Mr. Hook men- 

 tioned several liquors that by their working upon one another 



* New Experiments touching Flame and Air. 

 t Oldenburg. 



