Polytechnic Association. 895 



The President — I will give Mr. Parker credit for one thing. He 

 announced in 1851, that the distance of the earth from the sun, instead 

 of being 95,000,000 of miles, as was then supposed, was only about 

 92,000,000. Now it turns out from the most recent and reli- 

 able investigations — those of Prof. Newcomb, of Washington — that 

 the distance of the earth from the sun is but little more than 

 92,000,000 of miles. Here is a coincidence which is certainly worthy 

 of remark. 



Mr. Parker — I arrived at that result as a strictly mathematical 

 problem ; and it is contained in my book, on the Quadrature of the 

 Circle, in which I claim that I have demonstrated the exact quadra- 

 ture oi the circle. 



Dr. Yan der Weyde — In answer to Dr. Smith, I am willing to give 

 credit to the paper which has been read, for its ability ; but it is not 

 true. That is the trouble. 



Dr. L. Bradley — If there is a rule of multiple proportion applying 

 to the earth and moon, it ought to apply to the other planets ; but it 

 cannot apply to any planet having more than one moon. It cannot 

 apply to the moons of Jupiter, Saturn or Uranus. 



The President — Perhaps Mr. Parker would say that it might apply 

 to the mean motion of all the moons. 



Dr. L. Bradley — I am willing to concede that the imagination of 

 the gentleman has been very profound; but my imagination and 

 reflection led me in an opposite direction. Every body, every mole- 

 cule, is in motion. There can be no motion without something to 

 cause it. Matter is as universal as space ; and wherever there is mat- 

 ter there is motion. "Whatever is in motion, I think, is moved by a 

 projectile force. 



Dr. J. W. Richards — I understand that it is all attraction and no 

 projection. 



Dr. L. Bradley — It is true that gravitation has originated all the 

 projectile force in the earth or the planets. The revolution of the 

 earth on its axis, or in its orbit, the revolution of the moon in its orbit, 

 all the motions of worlds as well as of molecules, are caused by gravi- 

 tation. 



A Chinese Puzzle. 



Prof. J. Y. C. Smith exhibited a puzzle, consisting of several pieces 

 of wood connecting colored threads, which changed in number and 

 color as the central pieces were moved. 



Dr. Yan der Weyde explained the construction ; the threads were 



