238 



SCIENCE. 



[Vol. IV., No. 84. 



been made under Prof. Thurston's direction, shows 

 that the final deduction is substantially the same for 

 all the usually attainable conditions of practice, and 

 further, that, of all the available fluids, steam is 

 fortunately the best. 



That the results of scientific investigation may be 

 the more readily appreciated, it is necessary that the 

 study of physical science should be more thorough 

 in our schools. The stereotyped argument for the 

 retention of the old system of education to the ex- 

 clusion of the new, was, and is to-day, the assertion 

 that the old system strengthened the intellect and 

 broadened the views of the student, while the new 

 subjects are merely useful ; but the wisdom and the 

 expediency of a modification of old ways, in this re- 

 spect, is now rapidly becoming acknowledged, and 

 the new education may be considered as fairly and 

 safely introduced. Science will never, we may be 

 sure, displace entirely the older departments of 

 education; but science will henceforth take a place 

 beside them as no less valuable for mental disci- 

 pline. 



With science recognized as a respectable companion 

 of the dead languages, we shall have better trained 

 students, — students who will be better able to lead 

 in the industries, aud so aid material prosperity. As 

 it is the duty of government to so regulate affairs that 

 each man may have the power of improving his con- 

 dition to the utmost, so will it be the duty of science 

 to point out to government how it may direct its 

 regulations to the greatest advantage of the individ- 

 ual. Men of science, each in his own department, are 

 the natural advisers of the legislator. Citizens and 

 legislators are both entitled to claim this aid from 

 those who have made the sciences of the several arts 

 their special study, and from those who have devoted 

 their lives to the study of the sciences of government, 

 of social economy, and of ethics. 



Of all the many fields in which the men of science 

 of our day are working, that which most nearly con- 

 cerns us, and that which is of most essential impor- 

 tance to the people of our time, is that department 

 of applied science which is most closely related to 

 the industries of the world, — mechanics. The de- 

 velopment of new industries becomes as much a part 

 of the work of science in the future as is the improve- 

 ment of those now existing. The new industries 

 must evidently be mainly skilled industries, and must 

 afford employment to the more intelligent and more 

 finely endowed of those to whom our modern systems 

 of education are offering their best gifts. The enor- 

 mous advancement of the intellectual side of life 

 must inevitably, it would seem, result in the pro- 

 duction of a race of men peculiarly adapted to such 

 environment as science is rapidly producing. Thus 

 accomplishing, under the guidance of science, such 

 tasks as lie before him to accomplish, the ' com- 

 ing man,' with his greater frontal development, his 

 increased mental and nerve power, his growing en- 

 durance and probably lengthening life, will be the 

 greatest of the products of this scientific develop- 

 ment, and the noblest of all these wonderful 

 works. 



THE CRYSTALLINE ROCKS OF THE 

 NORTH-WEST. 1 



Until very recently, it has been the practice of 

 geologists, almost without exception, to refer every 

 crystalline rock in the north-west either to the 

 Huronian or to the Laurentian. But when, on more 

 careful examination, it is found that this nomencla- 

 ture is imperfect, we are thrown into much difficulty 

 and doubt. In order that some of the difficulties of 

 the situation may be made clear, Professor Winchell 

 proposed to review concisely the broad stratigraphic 

 distinctions of the crystalline rocks that have lately 

 been studied in Michigan, Wisconsin, and Minnesota. 

 Omitting the igneous rocks, which in the form of 

 dikes cut through the shales and sandstones of the 

 cupriferous formation, and are interbedded with 

 them in the form of overflows, we may concisely 

 arrange the crystalline rocks, disregarding minor dif- 

 ferences and collating only the broad stratigraphic 

 distinctions, in the following manner, in descending 

 order: 1°. Granite and gneiss with gabbro; its 

 thickness is unknown, but certainly reaches several 

 hundred feet. 2°. Mica schist; maximum thick- 

 ness, five thousand feet. 3°. Carbonaceous and 

 arenaceous black slates, and black mica schists; 

 thickness, twenty-six hundred feet. 4°. Hydro-mica 

 and magnesian schists; maximum thickness, forty- 

 four hundred and fifty feet. 5°. Quartzite and 

 marble; normal thickness, from four hundred to 

 a thousand feet. 6°. Granite and syenite with horn- 

 blendic schists; thickness unknown, but very great. 



These six great groups compose, so far as can be 

 stated now, the crystalline rocks of the north-west. 

 Their geographic relations to the non-crystalline rocks, 

 if not their stratigraphic, have been so well ascertained 

 that it can be stated confidently that they are all 

 older than the cupriferous series of Lake Superior, 

 and hence do not consist of, nor include, meta- 

 morphosed sediments of Silurian, or any other age. 

 The term ' Silurian ' here is understood to cover noth- 

 ing below the base of the Trenton. 



Examining these groups more closely, we find: 

 1°. We have, beneath the red tilted shales and sand- 

 stones, a great granite and gabbro group. The gab- 

 bro is certainly eruptive, but the associated granite 

 and gneiss are probably metamorphic. The gabbro 

 does not always appear where the granite is present; 

 but in other places these rocks are intricately mingled, 

 although the gabbro can be considered in general as 

 the underlying formation. 2°. Below this granite 

 and gabbro group is a series of strata that may be 

 designated by the general term 'mica schist group.' 

 This division is penetrated by veins and masses of 

 red biotite-granite, which appear to be intrusive in 

 somewhat the same manner as the red granite in the 

 gabbro. These granite veins penetrate only through 

 the overlying gabbro and this underlying mica schist. 



1 Abstract of an address to the section of geology and ge- 

 ography of the American association for the advancement of 

 science at Philadelphia, Sept. 4, by Prof. N. H. Winchell of the 

 University of Minnesota, Minneapolis, Minn., vice-president of 

 the section. 



