VOL. LXX.] PHILOSOPHICAL TRANSACTIONS. 697 



perior to any air I have yet found in England; for 1 measure of it with 1 of 

 nitrous air occupied 0Q7. The common air, as I found it in my lodging, was at 

 098. The wind had not shifted much, though I cannot ascertain the exact point 

 from which it then blew. It seems probable, from the foregoing experiments, 

 that tiiough in general the sea air surpasses the land air in purity, yet there are 

 the same inconstancies in its degree of goodness as in the land air. 



This experiment being finished, I closed my inquiries at Ostend, and set off 

 for Bruges. We arrived at dark, and about 7 in the evening I tried the common 

 air of that place, and found it inferior in purity to that of Ostend in more than 

 10 experiments; 1 measure of it with 1 of nitrous air occupied about 105. I 

 had the mortification to find the stoppers of the phials, in which I had kept the 

 air of Ostend, all loosened, so that I could not make any comparative trial with 

 both airs. Nov. 8, I set out for Ghent, where I spent the next day, Nov. Q. 

 I tried the air of that place about 3 in the afternoon, and found it better than 

 that of Bruges; for 1 measure of it with 1 of nitrous air occupied about 103, in 

 several experiments. 



As all the following trials with common air are made in the same way as the 

 foregoing, viz. by mixing 1 measure of common with 1 of nitrous air, I will 

 hereafter only mention the numbers of the result, for the sake of abridging the 

 paper, by avoiding continual repetitions. Nov. 12, at Brussels, I found the air, 

 at 7 o'clock in the evening, at 105|^. Nov. 13, the air of the lower part of the 

 city at 106, that of the highest part at 104; the weather was rainy and damp. 

 It is a common opinion at Brussels, that the air in the lower parts of the citv is 

 more unwholesome than in the higher parts. Nov. 14, the air of the lower and 

 higher parts of the city of the same goodness, each being at 103 ; the weather 

 was fair and frosty. Nov. 15, the air was the same as yesterday in both parts 

 of the city; the weather fair and cold. Nov. 22, I arrived at Antwerp, where 

 I found the air in the evening at 109-i-; the weather was rainy, damp, and cold. 



Nov. 23, I set out for Breda. I filled a phial with air, when I set out from 

 Antwerp at 8 in the morning. I also filled a phial with air on the middle of the 

 heath or common called De Lange Hey : the weather was remarkably close and 

 damp. I tried these 2 airs at night, at Breda; that of Antwerp was found at 

 106; that of Breda the same ; that of the heath at 305^. Nov. 25, I examined 

 the air at Breda in the morning, about 1 1 o'clock, the weather being fair, cold, 

 and inclining to frost; it was at 102. At 7 in the evening it was at 103. Nov. 

 25, the air at Breda was at 104; the weather rainy and cold. Nov. 26, the air 

 was in the morning and in the evening 103; the weather very rainy, cold, and 

 stormy. 



Nov. 27, I set out from Breda for Rotterdam, and crossed the water at the 

 Moordyke. I tried the air at the Moordyke close to the water, and found it at 



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