C 65 ] 



in relation to its permeability, the whole of the air 

 difcharged by the pump will iffue through the more 

 permeable parts of it, without affecting, in any de- 

 gree, the kfs permeable ones. 



3^//. In cargoes heated in any degree, and in 

 thofe infefted by that worm which fallens grains to- 

 gether by a web, the parts mofl: affefted become 

 much more clofe and denfely packed together than 

 the reft, either by the fwelling of the heated grains, 

 or the web and dung of the worms which occupy 

 the intervals between the grains. 



If fo, the parts of a cargo which require the 

 moft ventilation will receive the leaft; but in all cafes 

 it feems likely that the air difcharged will not regu- 

 larly permeate the whole of the cargo, but will pafs 

 through the parts where the grain lies lighteft, and 

 leave untouched thofe parts where it is moft clofely 

 packed together. 



ANSWER 



To the preceding ObjeSlibnsk 



THAT though the holes appear numerous, they 

 muft be fmall, left the corn gain admiffionj and many 

 (efpecially of the uppermoft) will be nearly, if not 

 totally ftopped, by the preflure of the grains upon 

 them. That the pipes which convey the air towards 



VOL. VIII. p the 



