50 Dr. dobson’s Account of the Harmattan, 
four or five days, the fcarf Ikin peels off, fir ft from the hands 
and face, and afterwards from the other parts of the body, if it 
continues a day or two longer. Mr. norris obferved, that 
when fweat was excited by exercife on thofe parts which were 
covered by his cloaths from the weather, it was peculiarly 
acrid, and tailed, on applying his tongue to his arm, fome- 
thing like fpirit of hart’s-horn diluted with water. 
As the date of fait of tartar placed in the open air, and the 
quantity evaporated from a given furface of water, are obvious 
proofs of the comparative moiilure or drynefs of the atmofphere, 
I defired Mr. norris to put the Harmattan to each of thefe 
tefls ; and particularly to moiflen fait of tartar ad deliquium , and 
expofe it to the night air during the time that the Harmattan 
was blowing. The following is the account of the refult of 
thefe experiments. Salt of tartar will not only remain dry 
during the night as well as in the day ; but, when liquified fo as 
to run upon a tile, and expofed to the Harmattan, becomes per- 
fectly dry in two or three hours ; and, expofed in like manner 
to the night air, will be dry before morning. 
With refpedl to evaporation Mr. norris fays, “ I fixed the 
tin veffel, with which you favoured me, on a grafs plat 
4C behind my houfe, upon a Hand four feet high, and expofed 
6i by its lituation moft part of the day to the fun, but ihel- 
* ■ tered in fome meafure from the wind by the houfe.” 
