540 



IHILOSOPHICAL TRANSACTIONS. 



[anno 177g. 



Mr. De Luc this is l°65. That the mean motion of the boiling point at 27.g08 

 inches, for 1 inch, is = 1°.779; by Mr. De Luc = 1°.73. And lastly, that 

 the mean motion of the boiling point, at 2Q.g25 inches, for 1 inch, is = 1°.709; 

 by Mr. De Luc = 1°.59. It should follow then, that, within the limits of mv 

 experiments, the alteration or motion of the boiling point is greater by ^ than 

 from that gentleman's observations; that the heat of boiling water is not directly 

 in the simple ratio of the height of the barometer, nor yet is the progression so 

 rapid as Mr. De Luc observed it. 



I will now add the annexed 

 general table for the use of 

 artists in making this instru- 

 ment, both according to my own 

 observations, and those of Mr. 

 De Luc, that the preference may 

 be given as it shall be thought 

 due ; not that it is a matter of any 

 great consequence which is made 

 use of under small variations of 

 the atmosphere; but even under 

 these circumstances, the object of 

 wish to verify a new theory, or aim at accuracy in these days of precision. 



XXVI. Account of a neiv Kind of Inflammable Air or Gas, tvhich can be made 

 in a Moment without Apparatus, and is as fit for Explosion as other In- 

 flammable Gases in Use for that Purpose; with a new Theory of Gunpoivder. 

 By John Ingenhonsz., M.D., F. R. S. p. 376. 



The important discoveries on different kinds of air have opened a new field 

 for one of the most pleasing and interesting scenes which ever were exposed to 

 the contemplation of philosophers, and therefore could not fail of exciting in 

 the lovers of natural knowledge a decided curiosity to see the pursuit of such 

 striking novelties, and an almost irresistible temptation to imitate them, and to 

 pursue farther the road already so far opened by Priestley, Fontana, Lavoisier, 

 and other learned men. Who can, indeed, without the greatest satisfaction, 

 look, amidst many other objects of admiration, on the discovery of that new 

 aerial fluid, which in purity and fitness for respiration so far supasses the best 

 atmospherical air, that an animal protracts his life 5 times as long, or even more, 

 in it than in common air of the best quality? Dr. Priestley, the first who dis- 

 covered this wonderful fluid, extracted it from bodies vvhicii we should rather 

 have suspected to have contained deleterious exhalations. He afterwards found 

 it existed in many other bodies in which the most accurate observer never 

 found any thing of an approaching nature. 



