[ 2 2 7 ] 
above fpace, which gives the velocity of the wind at 
the rate of 9.9 Englifh miles per hour. 
Thus, by having feveral lines in different directions 
of a known length marked upon the ground, one 
may eafily (and with great accuracy, I imagine), 
meafure the velocity of the wind. If a perfon was 
provided with an inftrument formeafuring the force of 
the wind, it would perhaps be worth while to obferve, 
whether, when the velocities of different winds 
were the fame, (or nearly fo) tjae forces of thefe winds 
did not vary with the feafons 6f the year, the points 
of the compafs from which the wind blows, and all'o 
with the different ftate of the barometer and thermo- 
meter, fince the momentum of the wind depends not 
only upon its velocity, but alfo upon its denfity. 
From the end of March 1765, to the end of 
March laft, we, in this part of Scotland, had very 
little rain, and lei's fnowin proportion ; our rivers were 
as low, through the winter, as they ufe to be in the 
middle of fu miner; fprings failed in moft places, and 
brewers and maltfters were obliged, even in winter, to 
carry their water at a conliderable diftance; I was 
much afraid there would not be moifture enough in 
the earth for the purpofes of vegetation, if this feafon 
fhould fet in as dry as the former, before we got a 
new fupply of rain. In the end of March laft, we 
had a fall of fnow ; and, as I did not remember to 
have ever read an account of fuch an experiment, I 
wifhed to be able to determine, to what quantity of 
rain this fall of fnow was equal. 
The fnow had been falling from five o’clock the 
former evening, till ten o’clock next day; about eleven 
o’clock I meafured the depth of the fnow, and found 
G g 2 it 
