CHEMICAL SCIENCE. 221 



be distinguished on account of its ammonia above that of the ocean in 

 an east wind. 



Continued observations on the state of the atmosphere, made since 

 the reading of this paper before the American Association, show 

 that the quantity of ammonia in the atmosphere is subject to con- 

 stant variation. In the summer, when vegetable and animal decay 

 is most rapid, the quantity is at a maximum, and afterwards decreases 

 regularly until the winter season, when it is at a minimum. 'Phe 

 following table shows the amount of ammonia found in the atmosphere 

 at thirteen different analyses. 



Ammonia in 



Date. 1,000,000 parts, 



by weight of air. 



1. July 3 42.9995 



2. July 9 46.1246 



3. July 9 47.6308 



4. September 1 to 20 29.7457 



5. October 11 28.2396 



6. October 14 25.7919 



7. October 30 13.9315 



8. November 6 8.0953 



9. November 10, 12, and 13 . . . 8.0953 



10. November 14, 15, and 16 ... 4.7066 



11. November 17 to December 5. . . 6.1328 



12. December 20 and 21 . . . 6.9885 



13. December 29 . 1.2171 



SINGULAR COMBINATION OF NITROGEN. 



WOHLER, of Germany, has ascertained that the crystals found in 

 the slag of some furnaces, and supposed to be pure titanium, con- 

 tain both carbon and nitrogen in proportions corresponding with the 

 formula Ti Cy + 3 Ti 3 N. This fact gives us entirely new ideas of 

 the nature of nitrogen, a body supposed to be distinguished above all 

 others for its tendency to take on the gaseous form when its compounds 

 are subject to heat. Letter of Prof. Liebig to Prof. Horsford. 



19* 



