SS8 Prof. Loom Is o« the determination of differences 



Potash 30-50 



Soda 11-30 



Lime 10*42 



Magnesia 9-13 



Peroxide of iron .... 2-15 



Oxide of copper .... trace 



Oxide of manganese . . . trace 



Sulphuric acid ..... 6-48 



Chlorine 13-33 



Carbonic acid 10-04 



Silica 1-58 



Charcoal 11-78 



106-71 



Omitting the charcoal and carbonic acid, and combining 

 the chlorine as before, we have as follows : — 



Potash .... 



Lime 



Magnesia . . . 

 Peroxide of iron . 

 Oxide of copper . 

 Oxide of manganese 

 Chloride of potassium 

 Chloride of sodium 

 Sulphuric acid . . 

 Silica .... 



36-23 

 12-72 

 11-14 



2-62 

 trace 

 trace 



1-58 

 25-87 



7-91 



1-93 



100-00 



The molasses and sugar came from the same manufactory, 

 and were made from the same sugar-cane. 



Lin. Letter from Professor Loomis of the New York Uni- 

 versity/ to Lieut. -Colonel Sabine, Foreign Secretary/ of the 

 Royal Society^ on the determination of differences of Longi- 

 tude made in the United States hy means of the Electric 

 Telegraph, and on projected observations for investigating 

 the Laws of the great North American Storms. 



Dear Sir, New York University, Aug. 2, 1847. 



I HAVE been for some time engaged upon a work in which 

 )'0U may perhaps feel some interest, — it is the exact de- 

 termination of the difference of longitude between New York, 

 Philadelphia and Washington, by means of the magnetic 



