AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. 69 



to illustrate the history of electrical science and electrical art. Writing as a 

 physicist, I would remind naturalists, that it was the careful study of the powers 

 of the torpedo that first enabled electricians to understand some of the most im- 

 portant laws of action of their artificial machines and batteries. I have elsewhere 

 pointed out, that in Cavendish's "Account of some Attempts to Imitate the Effects 

 of the Torpedo by Electricity" will be found the first enunciation of that dis- 

 tinction between intensity and quantity as affecting electrical phenomena, which 

 has since proved so important a guide to the explication of electrical problems. 

 Faraday dwells largely on this point, nor does it admit of the slightest doubt, that 

 inorganic electricity, both as a science and an art, is very largely indebted to organic 

 electricity in it for the explanation of the laws which it obeys, and for the con- 

 trivances by which it works. 



AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. 



ON THE FORMATION OF CONTINENTS. — BT PROFESSOR BENJAMIN PEIECE, OF 

 CAMBRIDGE, MASS. 



The interest which attaches to the comprehensive theory embraced in this im- 

 portant communication of Professor Peirce, tempts us to print the followino- un- 

 authenticated abstract, in the absence of any more trustworthy report. In justice 

 to the author, however, it must be borne in remembrance that it is derived from 

 the reports of the Montreal press ; and, at best, only serves to indicate the 

 author's line of argument. 



Prof. Peirce remarked that the pi'ineiple lines of the continents are arcs of great 

 circles tangent to the polar circles. Any globe will illustrate thi-. The eastern 

 coasi- of South America and the western coast of Eur.'pe are in such a line. So 

 also are the eastern coast? of Africa, Asia, and North America. The western side 

 of Hindostan is tangent on the other side. So also are the lines of Sumatra, the 

 western coast of America, and th ■ longer line of New Zealand. The western 

 coast of Africa, he said, was no doubt fully parallel. There were other lines 

 tangent to the tropics — tlie northern line of South America and the range of islands 

 of the Pacific. This seemed to indicate that the sun had some ioflaence in forming 

 the lines of continents. The difference of temperature caused by the sun's rays 

 was very considerable ; enough, as we saw, to keep portions of the earth in a state 

 of fluidity while others were solid. For a large portion of the year the sun was 

 near one or the other of the tropics, and it might be expected to exhibit its power 

 in this way by producing lines of cleavage, strorgly tending to form the outlines 

 of continents, for the instant the earth should shrink so far that the crust should 

 be too large for it, then the flexure must take place along the lines of natural 

 cleavage. Then the phenomena of freezing showed that there was a tendency to 

 lines perpendicular to these, which would give lines nearly tangent to the tropics. 

 One or the other of these lines would be the bottom of the ocean, and a corres- 



