VOL. LXV'III.J PHILOSOPHICAL TRANSACTIONS. 323 



by the water in its passage through it); after half an hour, still \Q5; so that no 

 diminution following, it was known to be mephitic. August 30th, the same 

 quantity of the air of his garden, with the nitrous, occupied 205 ; after half an 

 hour it was diminished to 145, which being deducted gave 6o, the state of the 

 air that day: and so of the rest. The medium state of the air of the atmosphere, 

 in upwards of 200 experiments, was 6o° or 6l°. 



Exp. 1. Sept. 13th, it was in the worst state Dr. W. ever observed it, 58°, 

 the barometer being 30.30, thermometer 69, with a calm, clear sky, wind s. e. 

 air dry and sultry, no rain having fallen for above a fortnight; on the same day 

 a slight shock of an earthquake. — Exp. 3. Sept. 21, a high wind cleared the air, 

 barometer 29. 50, thermometer 52°, the air was 64°. It was the same Oct. 5, 

 the wind high and westerly. This was the purest he ever observed. — Exp. 4, 

 He only observed it so good as 68° in 3 instances, Aug. 16, Sept. 20 and 29; 

 these were all showery days, with a brisk wind. — Exp. 5. As to the influence of 

 the different winds on one atmospheric air, the experiments are as yet too few to 

 ascertain it. He generally found it the purest during westerly winds, and the 

 worst when it blew from the easterly points. — Exp. 6. The difference of the air 

 a little way out of the city, from that in the city itself, is perceptible enough. 

 Aug. 9th, the air of the city was 59°, beyond the city walls 62°. On the llth 

 of the same month, the first was dO°, the last 62°. — Exp. 7. Common air being 

 briskly agitated with water for half an hour, was found to be made worse. In 

 one experiment it was reduced from 59" to 57°; in another, from 61° to 59°; in 

 a 3d, from 6l°to 5/°; in a 4th, from 62° to 58°. Air obtained from glazier's 

 putty by the nitrous acid was meliorated by the same process. 



In order to find the effects of animal exhalations on air, the following experi- 

 ments were made. Exp. 8. The air of his bed at night he found to be 62°, the 

 next morning it was reduced to 58°; this was several times repeated. The dimi- 

 nution here will appear very considerable on observing that it was the effect of 

 the breath, &c. of a single person, in a large, airy room, the bed-curtains al- 

 ways open, except on the side facing the window, which is quite open to large 

 gardens, and never shut with curtains. It fully shows the unwholesomeness of 

 small rooms, close beds, &c. especially in diseases. — Exp. Q. Some air which he 

 had respired as long as could be without manifest inconvenience, was by it re- 

 duced from 62° to 40°. This illustrates the preceding experiment. — Exp. 10. A 

 small piece of fresh veal was put into a phial containing 8 ounces of common air 

 and suffered to remain 24 hours: the flesh was then perfectly sweet, but the air 

 was much injured, being diminished from 64° to 55°. Being left together 24 

 hours longer, the air was reduced to 10°, or rendered nearly mephitic; yet the 

 flesh was not putrid, only smelling rather faint and musty. It is evident, from 

 hence, that something had escaped from the flesh, w hile yet void of any putrid 



T T 2 



