Photomtttr.— Fecundation of FegdabUs. ^ig 



deduced from the number of degrees indicated on the fcale. It may not be fuperfltious to 

 obferve- that, on expofing the humid coat, to freeze, tjie liquor ftiould be deprefled to the 

 loweft point, by touching the upper ball witli tlie hand, elfe, during the aft of congelation, 

 the inftrument is liable to be deranged. 



By inferting thefe additional remarks in your next number, you will much oblige 



SIR, your molt obedient fervant, 



Januarj 6, iSoo. JOHN LESLIE. 



P.S. An eafy and expeditious method ha$ fince occured for obtaining, with remarkable 

 accuracy, the graduation of the fcale after the compound tube is bent. To the bottom of 

 a fmall faucer faften, with foft cement, the inftruments to be graduated, difpofed at in- 

 tervals, the ftandard one in the centre, in a vertical pofition, with temporary fcales afiixed, 

 and prepared to a6t as hygrometers. Set this faucer on a fmooth earthen plate : then take 

 a tall glafs receiver, and pour into it fome concentrated fulphuric acid, and keep turning 

 it round and gradually inclining it till the whole of the infide is completely moiftened. In 

 this ftate, invert the receiver over the inftruments, and let it Hand on the plate, putting at 

 the fame time a few drops of the acid about the rim. The air thus included will quickly ac- 

 quire a drynefs of 50 or 60 degrees, which will continue without any vifible alteration for » 

 quarter, or perhaps half, an hour. The relative proportions of the diiFerent fcales may 

 therefore be noted with the utmoft precifion. With two nice correfpondcnt thermometers, 

 one of them having its bulb covered with wet bibulous paper, the ftandard inftrument 

 could firft be conftrutled. By attending to thofe diredions, I fliould prefume that even a 

 common artift might qualify himfelf to prepare the inftruments. I will only add, that for 

 the hygrometer it is preferable to blow both balls of colourlefs glafs, and cover the lower 

 one with a bit of gold beater's fkin. 



XI. 



An Account c/Jomc Experiments on the Fecundation of Vegetables. By Thomas Andrew 



. Knight, Efq. 



{^Concluded from page 460.) 



An the courfe of the preceding experiments I could never obferve, that the charafler 

 either of the male or female in this plant at all preponderated in the ofl^spring -, but as this 

 point appeared Interefting, I made a few trials to afcertain it. And as. the foregoing ob- 

 fervations had occurred in my experiments, made principally to obtain new and improved 

 varieties of the pea for garden culture, I chofe for a fimilar purpofe the more hardy varie- 

 ties, ufually fown in the fields, fiy introducing the farina of the largeft and moft luxu« 

 riant kinds into the bloflbms of the moft diminutive, and by reverfing this procefs, I found 



3S2 that 



