LATENT HEAT.

lOG

serviceable; and therefore we find the formermore ready to adopt such discoveries as promise tobe really advantageous, than the latter, who, hav-ing no other test of the value of a novelty buttime and experience, at first oppose its introduc-tion. The well-informed are, however, fre-quently disappointed in their most sanguine ex-pectations, and the prejudices of the vulgar,though they often retard the progress of know-ledge, yet sometimes, it must be*admitted, preventthe propagation of error.—But we are deviatingfrom our subject.

We have converted steam into water, and arenow to change water into ice, in order to renderthe latent heat sensible, as it escapes from thew r ater on its becoming solid. For this purposewe must produce a degree of cold that will makewater freeze.

CAROLINE.

That must be very difficult to accomplish inthis warm room.

MRS. B.

Not so much so as you think. There are cer-tain chemical mixtures which produce a rapidchange from the solid to the fluid state, or thereverse, in the substances combined, in conse-quence of which change latent heat is either ex-tricated or absorbed.