of Heat and Cold.
31
pell'd up about three inches and an half.]
And yet, if my memory do not much deceive me, I have found, that by mixing Salt of Tartar with another Salt, the Texture of the fixt Alkali was so alter'd, that upon the affusion of spirit of Verdigrease, (made without spirit of Vinegar and spirit of Wine,) though there ensued a great conflict with noise and bubbles, yet, instead of an Incalescence, a considerable degree of Coldness was produced.
EXPER. X.
'Tis very probable that further Trials will furnish us with more Instances to shew how the Production of Cold may in some cases be effected, varied, or hinder'd by Mechanical Circumstances that are easily and usually overlook'd. I remember, on this occasion, that thoughin
