ELISHA MITCHELL SCIENTIFIC SOCIETY. 83 



The equation of SA is 



h 



2 



Substituting this value in (i), the cut S is at once 

 obtained. Denoting the cds. of S by (.r^\ j'^^) and the cds. 

 of C by (^\ y), and substituting in (3), CS is known. 

 Measure tWs distance, and fix stake at S. 



The same course of reasoning applies in finding the cuts 

 at P^ and T. 



The writer has found this method more expeditious than 

 trial and error when the surface was much inclined. The 

 nuinerical computations did not require as much labor as 

 manceuvering with the rod and level. 



Since he has not seen the above method in any of the 

 books which have fallen under his eyes, he has been 

 induced to give it in the hope that it might prove useful, 

 as well as suggestive, to others under similar circumstances. 



Trinity College. N. C. 



ON THE DEVELOPMEXT AXD A SUPPOSED NEW 

 METHOD OF REPRODUCTION IN THE SUN-AN- 

 IMALCULE, ACTINOSPH.ERIUM EICHHORNIL* 



BY JOHN M. STEDMAN. 



Early in March my attention was called to an aquarium 

 which had been standing in my window during the winter, 

 and which contained anacharas and algae in great abundance, 

 but which now suddenly presented a quantity of light pink 

 substance on the sides of the jar. It was the appearance of 

 this pink-colored material among the debris of decaying 

 and growing algse that attracted my attention. Accord- 



Atner. Soc. Microscopists, i8S8. 



