A. It is composed of nitrogen and oxygen in the proportion of seventy-seven of nitrogen and 23 of oxygen.
Q. Of what does water consist?
A. Hydrogen and oxygen in the proportion of one of hydrogen to eight of oxygen by weight.
Q. What are the different kinds of heat?
A. Latent heat, sensible heat, and sometimes total heat.
Q. What is meant by latent heat?
A. Heat that does not affect the thermometer and which expends itself in changing the nature of a body, such as turning ice into water or water into steam.
Q. Under what circumstances do bodies get latent heat?
A. When they are passing from a solid to a liquid state, or from a liquid to a gaseous state.
Q. How can latent heat be recovered?