720 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



of rotation and revolution of the planets appeared perfectly reg- 

 ular, unchangeable; also their relative mean distances; there 

 appeared to be no resistant medium in the planetary space which 

 possibly could retard their motion; our planetary system appeared 

 a perfect perpetu'dm mohile, and, indeed, was pointed at as a per- 

 fect, frictionlcss, illustration of such; the time of rotation of the 

 earth appeared not to be changed to any perceptible degree since 

 2,000 years, the disturbances in the course of the planets found 

 by Newton, and caused by their mutual attractions, was demon- 

 strated by La Grange and Poisson to compensate themselves in a 

 certain long period of time. The temperature of the earth appeared 

 constant — an opinion still erroneously shai'ed by some philoso- 

 phers of the present day, — and the wearing awa}'- of the continents 

 by the action of waters in rivers, etc., appeared compensated by 

 the upheaving power of volcanic action. 



But to us, who have the good fortune to live in the latter half 

 of the nineteenth century, new facts have been revealed. I speak 

 here of the good fortune of living now; and indeed when we look 

 back only 200 or 300 years, and even less, and compare the man- 

 ner of life without the use of steam, electricity, or a thousand other 

 comforts of the present day, we must confess that, with our pre- 

 sent experience, the world, at that time, was scarcely wortli living 

 in. If the progress in the next century be as great as it was during 

 the last, the vital state of men a hundred ^^ears hence will lie of a 

 nature of which we cannot possibly conceive the details. If the 

 progress be little, then in future centuries our nineteenth will be 

 pointed at as the great era in which man learned to subject the 

 forces of nature, and made them subservient to his purposes, as 

 the era of the greatest progress the Avorld ever saw ; but I am 

 satisfied that the progress in the centuries to come will far outstrip 

 the progress made in former centuries. 



The discovery of Romer, in Denmark, almost 200 years ago, that 

 it takes the light eight minutes to reach us from the sun (which 

 corresponds with a velocity of 190,000 miles a second), was a 

 starting point of investigation in a new line, of which we at pre- 

 sent see the fruits. t 



The speal^er at this point explained how the planet Jupiter was 

 found. Next he gave an account of Prof. Alexander's fantasy on 

 light and Omnipresence, and after describing Herschel's penetrat- 

 ing telescope, with enlai-giug objective, he proceeded : 



Newton maintained that the light consisted of corpuscles thrown 



