Elements of agriculture and vegetation. To which is added, an appendix, for the use of practical farmers / [George Fordyce].

  • Fordyce, George, 1736-1802.
Date:
1796
Catalogue details

Licence: Public Domain Mark

Credit: Elements of agriculture and vegetation. To which is added, an appendix, for the use of practical farmers / [George Fordyce]. Source: Wellcome Collection.

    108/122 (page 104)
    FIG. VI. When two Particles P P are chemically com- bined, they may be confidered as united at the chemical Sphere of A£tion C, and now to have acquired one common Sphere of Mechanical Action M, their former Spheres of Mechanical Aftion being loft during their chemical Com- bination. FIG. VII. Thus a Particle of Volatile Alkali may unite chemically with a Particle of an Acid, forming Sal Ammoniac, in which they have one common Sphere of Chemical Attraction, at which they may unite with Copper, and when fo combined, the three Particles acquire one Sphere of Me- chanical Aftion. FIG. VIII. Subftances evaporate more or lefs readily ac- cording to the Preflure on their Surface; fup- pofe therefore, that a Fluid confifts of Rows of Particles ABC, the upper Row A has only the Preflure of the Atmofphere, but the next Row B, has both the Preflure of the Atmofphere, and the Preflure of the upper Row, therefore the upper Row A will evaporate moft readily, and as boiling Fluids are heated equally, and it will require a greater Heat to evaporate the Row B than the Row A, the whole Evaporation will take place from the Surface, APPENDIX-