CHEMISTRY. 505 



eniiig proceeds from the top downward to the depth of 9 to 12 inches of 

 its own accord. {Ghem. Netvs, L, 37.) 



Determination of Nitrogen by Combustion with Calcium Hydroxide. — 

 Prof. S. W. Johnson showed in 1873 {Am. Chemist, iii, 161) that the 

 mixture of sodium hydroxide and calcium hydroxide proposed by Will 

 and Varrentrapp as a reagent for converting organic nitrogen into am- 

 monia, for the purpose of analysis, may be advantageously replaced by 

 a mixture of sodium carbonate and calcium hydroxide. In the Annual 

 Keport of the Connecticut Agricultural Experiment Station for 1883, 

 the same chemist gives a series of analyses made with calcium hydrox- 

 ide alone, and the results warrant this further simplification of the 

 Will and Varrentrapp method for most substances ordinarily encountered 

 in technical work. A tube 14 inches long is recommended for the com- 

 bustion of 0.5 grams of substances containing 8 per cent, of nitrogen or 

 less. Cochineal solution is preferred as an indicator, being not seriously 

 attected by carbonic acid, quite sensitive in its reaction, and keeping 

 better than litmus. [Am. Chem. Journ., vi, GO.) 



Occurrence of Zinc in Drinking- 'Water. — Mr. C. W. Heaton reports find- 

 ing G.41 grains per gallon of zinc carbonate in a drinking water carried 

 from a spring through half a mile of galvanized iron pipe. The spring 

 water itself was very pure, containing no ammonia, only nitrogen as a 

 nitrate; this, however, was wholl3^ converted into ammonia by the zinc. 

 {Chem. Ifews, XLix, 85.) 



Prof. F. P. Venable, of the University of ;N^orth Carolina, also calls 

 attention to this impurity. The water from a spring 200 yards distant 

 was brought by galvanized iron pipes to a dwelling house, and. there 

 stored in a zinc-lined tank, which was painted with white lead. The 

 water became somewhat turbid and metallic- tasting, and its use for 

 drinking purposes was discontinued. Analyses were made after the 

 pipes had been in use about one year. A somewhat full analysis of the 

 spring water was made by Mr. J. C. Roberts. The anahvses of water 

 from the tank and directly from the pipe are carried out only so far as 

 zinc, iron, and tests for lead were concerned. The results are calcu- 

 lated in grains per gallon of 231 cubic inches : 



Analysis of spring. 



Grains. 



Silica.--' 2.45 



Lime • 23 



Magnesia 17 



Alkalies 43 



Chlorine 35 



Sulphuric acid 19 



Carbon dioxide (calculated) 45 



Total residue on evaporation 4.34 



