298 J. L. Rich — Stratigraphy of E. Netv Mexico. 



This statement, also, is evidently based upon the 

 confusion of the Upper Triassic Santa Eosa sandstone 

 ^yith the Permian Griorieta, for, though the latter extends 

 south to and beyond the railroad, the latter does not, 

 except close to or east of the Pecos. 



Baker's suggested correlation of the Glorieta with the 

 Shinarump is also based on the erroneous supposition 

 that the Glorieta sandstone of Glorieta Mesa is the same 

 as the sandstone at Santa Eosa. 



317 Railway Exchange Bldg., 

 Denver, Colo., 

 June 30, 1921. 



SCIENTIFIC INTELLIGENCE 



I. Chemistry and Physics. 



1. A New Reaction for Ammonia, and its Application for the 

 Detection of Nitrogen in Orgamc Substances. — C. D. Zenghelis 

 has devised a very delicate test for ammonia. His reagent con- 

 sists of a solution containing 20 per cent of silver nitrate and 3 

 per cent of commercial formaldehyde solution of 33 to 37 per 

 cent strength. The reagent should be prepared immediately 

 before use. When some drops of the reagent are placed upon 

 a small watch-glass and this is exposed to the action of ammonia 

 under a crystallizing disk a brilliant mirror of silver is formed 

 upon the surface of the drops of the reagent, or in the case of 

 very small quantities of ammonia, such as 0.000001 or 0.000002g. 

 brilliant rings of silver are formed around the edges of the drops. 

 In cases where the reagent begins to decompose spontaneously 

 silver is deposited in the form of a powder, and this does not 

 interfere with the reaction, provided that decomposition has not 

 gone too far. The test may be applied to a solution by placing a 

 small quantity of it in a rather short test-tube, adding a few 

 drops of caustic soda or sodium carbonate solution, covering the 

 mouth of the test-tube with a watch-glass, upon the lower, convex 

 side of which is a drop of the reagent and upon the upper side 

 is a drop of water for the purpose of cooling. Upon warming 

 the liquid in the test-tube until water begins to condense upon 

 the watch glass, around the drop of the reagent, then discontin- 

 uing the heating, the reaction soon appears in the form of a 

 silver mirror if ammonia is present. It is stated that a distinct 



