CHEMISTRY AND PHYSICS. 41 
and then sown with some of the nitrifying bacteria, which’ under the right condi- 
tions will change the ammonia to nitrites and nitrates. 
An examination of the public water-supply of the city of Marysville, Kan., 
showed the presence of what we considered large quantities of nitrates, so that 
the matter seemed of considerable interest. The results were as follows: 
[DINE ELE TEMOACOTE GN Green ckseigioing PCO Cre Reem meaner .075 parts per million. 
EMICSTIETINEN OT CAA NETL OWN Aes S =e) 3-6) cP aisis, 2 wc. 5 ss asec eikes ete eco betes 157 ue oe 
ROPE MAMUMUGLILCS anccch cat G2. 6% sjerets ol doary vie odes ejay teers trace. 
NMROSEMEIMEMILPALESs cessoric chavs cinralg, 2) iat 6 ho ei aoe 9.1015 uF 6 
On account of the large amount of nitrogen as nitrates, and because it seemed 
more than would be usually found in our ground waters, some twelve more 
samples of water from the same city were obtained, through the kindness of 
the superintendent. Comparative tests on equal quantities of water were made 
by the use of concentrated sulfuric acid and ferrous sulfate in cold solutions ; 
and the results were compared with those obtained with the quantitative analysis 
of the city supply alluded to. The results are as follows, arranging them ona 
scale of 1 to 4, the latter being the highest: 
City water-supply, three samples: 2, 3, 2 
Wells in the same city, eleven samples: trace, ;5,, 1, 1, 2, 2, 3, 3, 3, 4, 4. 
It was not thought to be worth the while to make quantitative analyses of 
each of these wells, as the point was so well shown that the city water-supply was 
about the average of the wells of the city in nitrogen in the nitrates. No exami- 
nation was made for nitrogen in nitrites, except in one case where only a trace 
was found. In this well there was found 10.6259 parts of nitrogen as nitrates, 
and both the free and albuminoid ammonia were a little higher than in the city 
supply. 
It is generally held that the nitrates indicate what Frankland calls ‘‘ previous 
sewage contamination ;”’ and, if this is true, it is of great importance in the study 
of waters that are used as a source of domestic supply. It is stated that water 
from the drainage of cow stables has been found to contain little free or ‘‘albumin- 
oid’’ ammonia, but to contain a large amount of nitrites and nitrates. Stoddart* 
claims that ‘‘natural waters can, at most, obtain but from 1.43 to 2.86 parts per 
million of nitrogen as nitrates, from other sources than animal matter; and prac- 
tically the whole of the nitrogen of sewage may be oxidized into nitric acid, with- 
out diminishing the risk involved in drinking it.”’ 
Professor Mason+ also quotes the results of analyses of rain-water, from vari- 
ous localities in Europe, as follows: 
JB yaySdlevavel, vay HE) OVel a cence Ee Cee Oe Rie CRM ot aon ol) parts per million. 
LESTE US IGE OTTERS Beto eGo aaa te” RAR Se on ae 22 
Scotland, near the Pi ea tee De ee Ae sbenelul ue a 
KS CUETO nee Serra ee tae ie en eR vars noe Ase hee NOU Ue a 
ae THOU RES (0) egey s sce B nA IN A Ne lo ae A Ree aS ee ee .08 oe a 
of Clasr once eee ens EES ae ae ES eee 63 es A 
Montsouris, Paris, average of 18 years. at Pees pale ue es 
The results of some experiments made coe Prof. on H. Failyer, { upon rain- 
water collected at the agricultural college are of interest in this connection. 
He reports that the different rains contained very different quantities of nitrogen 
in these forms: 
Maman nitrogen. ag nitrates, 2 0... 3:6). 50. cesses ete eee detect es 1.850 
MIME On ML TOPOM AS MILTALES, 225 05. de sive ee oe ad dives AF toe delete ns .029 
*Water-supply, Mason, p. 379. 
tLoc. cit. 
tTransactions Kansas Academy of Science, vol. xII, p. 24. 
