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291 



OBSERVATIONS concerning 



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markable phxnomenon; for the fouth fide of them, which 

 is, more immediately expofed to the rays of the fun, be- 

 come foon heated, and hatch the eggs contained in the grains 

 of wheat from the furface to about eighteen inches in depth, 

 \7hilft no worms or flies are found deeper, or on the north 

 fide. If the degree of heat which hatches the eggs in the 

 fouth fide of the ftack, and the degree in the north fide, 

 which preferves them without hatching, were afcertained 

 by a thermometer, it would lead us to a means ofpreferv- 

 ing the grain, either by keeping it cool, and thereby pre- 

 venting the hatcliing of the eggs, or heating it, fo as to 

 corrupt them, without injuring the corn; for the differ- 

 ence of warmth in which eggs maybe preferved, hatched, 

 or corrupted, is but fmall ; " 93 degrees of heat in 2 1 days 

 gives growth to the chick in an hen's egg, from a little fpeck 

 iato a perfect animal body; but the fame egg would be 

 rendered unfit for producing a chick by a greater degree 

 of heat, fcarcely enduring 100 degrees without prejudice 

 and a much lefs degree than 93, would not fuffice for 

 hatching it." The degrees requifite to hatch the eggs- of 

 thefe flies, to prevent their hatching, or to corrupt them, 

 iBight readily be known, by putting the fame kind of fly- 

 injured wheat in difl'erent open vellels, and keeping them 

 In different degrees of warmth, making 93, or the warmth 



of the prolific part of the flock, the medium ftandard. 



Another experiment, of great importance, in this enqui- 

 ry, fiiould be made at the fame time, to difcover whether 

 the eggs of thefe flies can be hatched, or the worms exifl:, 

 without the frequent accefiion of frefli air: This may be 

 made, by tying a bladder clofe over a vefl^el, containing the 

 above kind of wheat, and keeping it in the degree of 

 tvarmth that will hatch the eggs; and if the eggs in the open 

 veffel hatch whilft thofe in the covered one do not (which, 

 philofophy teaches us, will probably be the cafe) it proves 

 that fecuring the fiieaves of corn from the accefs of 

 frelh air, by covering them clofe in ftacks or barns, with 

 hay or flraw, &c, and keeping the threflied grain ia 



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