136 ESSAY 



well adapted for my purpose, as it readily admits 

 amongst its fibres the moisture, which forms on 

 its outer parts, and retains what it receives so 

 firmly, that I never but once had occasion to 

 suspect, that it suffered any portion of what it 

 had thus acquired to pass entirely through it. 

 The wool, which I used, was white, moderately 

 fine, and already imbued with a little moisture, 

 from having been long exposed to the air of a 

 room, in which no fire was kept. I divided it 

 into parcels of 10 grains each, and, immediately 

 before exposure, pulled the fibres of every 

 parcel somewhat asunder, so as to give it the 

 form of a flattened sphere, the greatest dia- 

 meter of which was about 2 inches. As in 

 doing this, I went by the judgment of my sight 

 alone, some little inequality, in point of size, 

 must have existed among different parcels, but 

 none, I think, sufficient to affect the accuraqy 

 of my conclusions from the experiments, in 

 which they were employed, more especially as 

 my conclusions scarcely ever rested upon single 

 trials. 



Previously to mentioning the results of any 

 of my experiments with these parcels of wool, 

 I think it right to describe the place, where by 

 far the greater part of my observations on dew 

 were made. This was a garden in Surrey, 

 distant, by the public road, about three miles 



