Page:Popular Science Monthly Volume 45.djvu/683

Rh Abrey in the Northwest, was exceptionally severe and occurred during a maximum period. In our daily observation of the sun we watched the spots during the previous summer, and were astonished at their size and number.

I can only add that when the expedition starts I hope to be one of the party. If it is organized on the lines I have laid down I should set out with an absolute assurance of getting there, and, what is of still greater importance, with an equal certainty of getting back again.



INERALOGY, as the observation of minerals, is of very ancient date, but such observation was very crude, for the old scholars grouped under one name a great variety of forms, some rocks and some minerals. The earliest writer was a Greek by the name of Theophrastus, who lived about three hundred years before the Christian era. A few centuries later the great naturalist Pliny recorded a number of personal observations. Then followed a blank period extending into the eleventh century, when Avicenna made his mineral classification. In this, the first classification, all minerals were divided into four groups—stones (= silicates), salts, inflammable bodies, and earths. In the next six centuries the only improvement was the substitution of term metals for earths. Through all these many years, it was the beautiful in form, luster, and color of the gems which attracted the attention of men both learned and ignorant. The question of origin was not considered; indeed, it was sacrilegious to think of such a problem, since these were objects of creation, whose genesis, like that of the gods, was not to be revealed to man. It was the work of many centuries to dispel these clouds of ignorance and superstition which blinded and hindered the advance of this study. The only light which did appear was that of the 