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310 



LIGHT, HEAT, 



Sect. XIII. 3. i. 



in refpe6l to the abforption of Its food, circulation of its juices, and 

 quantity of its fecretlons, and confequently to its more rapid growth; 

 but all increafe of ftlmulus becomes injurious by its excefs, and is cer- 

 tainly followed by debility ; as is feen in thofe of our own fpecies, 

 who are habitually kept in too warm rooms, or are accuftomed to 

 drink intoxicating liquors. 



Hence a wife gardener mufl; regard the acquired habits offender 



vegetables; the inhabitants of his green houfe, and thofe plants, 

 which have been expofed to a greater heat for any length of time, 

 ihould be gradually cooled, and watered with fubtepid water ; fincc 

 expofing them to the cold of this climate is otherwife liable to de- 

 ftroy their Irritability and occafion their death, 



4. The great cold produced by evaporation is now well under- 

 ftood. In all chemical procefles, where aerial or fluid bodies become 

 confolidated, a part of the heat, which was before latent, becomes 

 prefTed out from the uniting particles ; as in the inftant that water 



r 



freezes, or that water unites with quick lime. On the reverfe, when 

 folid bodies become fluid, or fluid ones become aerial, heat is abforbed 

 by the folution ; whence it may be faid in popular language, that all 

 chemical combinations produce heat, and all chemical folutions pro- 

 duce cold. This fhould teach the careful gardener not to water ten- 

 dry wind ; 



o 



warm 



der vegetables in the heat of the funfhine, or in a 

 left the hafty evaporation (hould produce fo much cold as to deflroy 



certainly from their having been previoufly 



them 



d th 



more 



much ftimulated by heat, and in confequence their power of life, 



; as further ipoken of 



ted 



Dr 



or irritability, having been already dlminlfhed ; 

 in Sed. XIV. 2. 2. 



III. I. The mechanical theory of ele6lrlcl 



Frenklln is believed by fome philofophers not fo well to explain the 

 various phenomena of ele6lriclty, as may be accomplKhed by an hy- 

 pothefis of the exifl:ence of two eledric fluids dlffufed together, and 

 flrongly attracting each other, one of them to be called vitreous, and 



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