Page:Popular Science Monthly Volume 18.djvu/555

Rh forms of matter into the three following classes, with the accompanying definitions:

1. —Substances whose molecules are composed either of those of other chemical elements of less atomic weight, or of such as are too low to be capable of molar aggregation, and therefore imperceptible to sense: formed during the progress of development of star-systems at temperatures higher than can be artificially produced, and hence too stable to be artificially dissociated.

2. —Substances whose molecules are composed of those of chemical elements or of other inorganic compounds of lower degrees of aggregation: formed in the later stages of the development of planets at high but artificially producible temperatures, and therefore capable of artificial decomposition; and constituting the greater part of the solid crust of cooled-off bodies, their liquid and a portion of their gaseous envelope.

3. —Substances whose highly complex and very unstable molecules are composed of those of chemical elements, inorganic compounds, or organic compounds of lower organization: formed on the cooled surfaces of fully developed planets at life-supporting temperatures.

 

HE world's life is one long day, in which events strike the hours. The hours strike, time moves on, till another stroke marks an advance which could only be that of the present moment, and to which all the minutes of the past have contributed. I seemed to hear that clock of the ages strike, the other day at my table, when a charming young Frenchman was explaining why he had come to America. It is humiliating to man, haughty in his mastery of this world, to find a successful antagonist, the least of creatures, microscopically small, and nameless often, till the baffled husbandman is obliged to write it in Greek or Latin characters upon the banner of his conquering foe. The Phylloxera is mightier than a German army; for the latter, once satiated, goes home, but the former apparently stays for ever. The Egyptians are again upon us; the plagues of Egypt, and perhaps, what is worse, the plagues of America, move across the world, devastating as they go. The contagion of evil seems to outrun that of beneficence in an unfair proportion. Creatures unconscious of what they do, which the microscope barely discovers, terrify whole nations, and give the lie to the arrogance of man. Somewhat as the old thought is now 