176 F. H. Storer—Schenbein’s Test for Nitrates, 
tion of the cometary bands, especially when regard is paid to 
the faintness of the light and the consequent difficulty of precise 
determination. Measurements of the first two bands, with the 
satisfactory, as it appears to be somewhat. less refrangible than 
its cometary analogue, as determined by the majority of obser- 
vations of the latter, though it agrees very well with some of 
them. Not improbably, however, the hydrocarbons existing m 
small quantities in some of the meteorites may be present im 
the comets in sufficient amount to modify their spectra some- 
what. 
Yale College, July 28, 1876. 
ArT. XXII.—Schenbein’s Test for Nitrates; by F. H. STORER, 
Professor of Agricultural Chemistry in Harvard University. 
act upon the nitrate in order that the iodo-starch reaction may 
oceur, does not in any case change the whole of the nitrate into 
a nitrite and no other nitrogenous product. The zinc oy 
fail, upon the one hand, to reduce the whole of the nitrate, 
action. Some of the nitrate is always changed, withal, t “ 
ammonium salt and so destroyed in so far as the power © 
reacting upon iodo-starch is concerned. 
These considerations have often been urged, and they ee 
undoubtedly familiar to most chemists. But in the lack o ® 
better, the iodo-starch test for nitrates has come into Vel 
general use and has been held in high estimation. The re™ if, 
of Carius must have struck scores of chemists, as it did mys® 
* Annalen der Chemie, 1874. clxxiv, 14, note. 
