Because spirituous drinks contain a large proportion of ALCOHOL, one of the constituents of which is _hydrogen_. The vital energies of the drunkard, being destroyed by excess, chemical agencies obtain an ascendancy, and it is supposed that the _hydrogen_ of the alcohol combines with the _phosphorous_ of the body to form _phosphoretted hydrogen_, which ignites spontaneously, and literally consumes the living temple. [Verse: "Drought and heat consume the snow waters; so doth the grave those which have sinned."--JOB XXIV.] Cases of spontaneous combustion are of rare occurrence. But they are sufficiently well authenticated by high medical authority, in many parts of the world, to present an awful warning to the inveterate drunkard. The cases of which we have read the particulars present details of the most appalling description. How signally the Almighty displeasure at intemperance is expressed, when the very drink which imparts the mad pleasure of intoxication is made the _direct_ instrument by which the drunkard is destroyed! CHAPTER XVI. 321. _Why does friction produce heat?_ Because all bodies contain _latent heat_, that is, heat that lies hid in their substance, and the rubbings of two bodies against each other _draws the latent heat to the excited surfaces_. 322. _Why does the rubbing of two surfaces together attract latent heat to those surfaces?_ Because it is a law of nature that _heat_ shall always attend _motion_; and it is generally found that the _intensity of heat_ bears a specific relation to the _velocity of motion_. 323. _What are the sources of heat?_ The _rays_ of the _sun_, the _currents_ of _electricity_, the _action_ of _chemicals_, and the _motion_ of _substances_. 324. _Why does water freeze?_ Because its latent heat is partly _drawn off_ by the surrounding air. 325. _Why does ice melt?_ Because the heat, once latent in the water, but drawn off by the air, _has returned_ to it, and restored the water to its former condition. [Verse: "So teach us to number our days, that we may apply our hearts unto wisdom." PSALM XC.] 326. _Why does water become steam?_ Because a larger amount of heat has entered into it than can remain latent in water. The water therefore expands and rises in the form of vapour, or _water attenuated by heat_. 327. _How many degrees of heat are latent, or hidden, in the different states of water?_ In thawing _ice_, 140 deg. of caloric become latent; and in converting the water into steam, 1,000 deg. more of caloric are be taken up. Therefore, _ice_ requires to take up 1,140 deg. of latent caloric before it becomes steam. 328. _What is the most modern theory of heat?_ It is this--that caloric, which produces heat, is an extremely _subtile fluid_, of so refined a nature that it possesses no weight, yet is capable of diffusing itself among the particles of the most solid bodies.