Page:Popular Science Monthly Volume 18.djvu/628

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It is undeniable that there is yet much to be done in this domain. But the results obtained by Ferrier are so encouraging that we hope this new way of studying cerebral physiology will be followed and explored with more care than ever.


A LUMP of coal—black and grimy, and repulsive to sight and touch as it is—is, perhaps, not the most promising subject that could be selected for Sabbath-evening reflections. But, if there are sermons in stones, why not in coal? The black thing, that we would rather not handle when we have any proper regard for cleanliness, becomes an object of interest when we find it exerting energy in the engine-furnace or shedding warmth and radiance around our household hearth. It becomes an object of yet greater interest when we come to learn its wonderful history; for every common bit of coal that we are accustomed to see has a history with which is wrapped up the story of one of the most interesting and critical periods in all geological time. It is the lessons and promises of this far-off history of the coal that constitute the theme for to-night.

Fifty years ago an attempt to tell the history of the coal would, no doubt, have seemed, to all but a very few, not only hopeless, but absurd. Since then the methods of questioning Nature and making her tell her own history have been so much improved, and have been, withal, so energetically applied, that very much, which our grand-fathers would have set down as past finding out, has become the mental property of every well-instructed schoolboy.

There are many different kinds of coal, and coal belongs to many different epochs in the world's history, but that which we find in the coal-fields of Iowa and Illinois may be taken as the type of what is usually understood, the world over, when coal is mentioned. Let us fix our attention on a piece of such coal. To extort from that expressionless thing any facts bearing on its history would seem discouraging enough. We may look at it just as long as we please; we may break it to pieces with the hammer and examine it bit by bit, and it is altogether likely that we will be left just as wise and just as hopeless as when we began. Pass it over to the chemist, and he will tell us that it is made up of combustible matter of which so much is fixed and so much volatile, with a certain percentage of earthy substances and traces, perhaps, of ever so many elements that we never heard of before. The information is interesting—in many respects it is of the highest importance—but for the purposes of the present discussion it amounts,