t 144 ] 



year the beft ? But thefe places will 

 not be known till fome accurate 

 method of examining the goodnefs 

 of common air be in general ufe. 



Is it not fomewhat probable, that 

 it is unfafe for the health of people 

 to fleep in rooms having windows 

 towards a fmall open place crouded 

 with the branches of a large tree, 

 fo hidden from the influence of the 

 fun as to receive but feldom its 

 rays? I remember to have heard 

 people fay, that it was unwholefome 

 to lit under a wallnut-tree, and that 

 they found themfelves affected by 

 its fhade. But I looked upon fuch 

 an apprehenfion as one of thofe 

 popular or vulgar errors which are 

 propagated from father to fon. I 

 mould now be inclined to think, 

 that an apprehenfion of fome mif- 

 chief might not be entirely ill- 

 grounded, 



