. Chemical Examination of Natural Waters. 223 
is, that the surface water of lakes is purer than that taken from 
‘some depth. Nos. 3, 8, and 10, also 2, 6, and 7, also 5 and 9, 
offer illustrations of this remark. The rivers also gather impuri- 
R ties as they draw near their mouths, the water from high up the 
tl 
being purest. It will also be seen that the number and 
al Siagortion of the ingredients vary in the same water. These re- 
sults were not a little interesting to the writer and his excellent 
assistant, Mr. Hunt, when after our labors were closed, we were 
for the first time supplind with the names of the various sources 
ftom whence the waters on which we had labored were obtained. 
The specific gravities of these waters were. taken, with a Wei 
eate balance, and, with ery | 
-Acglass bottle with a Facioamtid stopper was ; used for the purpose. 
_ The results were in some cases anomalous, giving for some of the 
Wwaters.a density less than that of pure water. But these differ- 
ences are so infinitesimal as to be easily accounted for by. the 
gaseous matters which these waters contain. The actual differ- 
ences from the density of pure water at 60°, afforded even by the 
Most dense of the waters examined in this research, affect on- 
ly the third place of decimals. Thus No. 11 has 87-811 parts 
of solid matter in a hundred thousand parts of water, or nearly 
"one per centum, yet its gravity differs from pure recently boiled 
Water distilled from glass by only.z.¢¢hrz¢- We should not look 
ore for a very appreciable increase of gravity in a water con- 
taining only three parts of solid matter in a hundred thousand. . 
le IIT shows the eapecite gravity. 
| ne 
= — 1-000060 a0 10000894 | near oT | ORNS 
ae J OS TO Pee 
E a a [aa FOOT jowane7T | Cour | | 
The water No. 11 (from a well in Boston) proved to be highly 
saline. One standard quarter gallon of the water was boiled with 
the previous addition of a known quantity of pure anhydrous 
carbonate of soda, which threw down, during the progress of the 
ebullition, all the earths and other bases present, except the soda, 
converting them of course into carbonates. Then by the well 
nown methods of analysis, the various ingredients were sepa- 
Tately determined, and the soda quantitatively. I give subjoined 
the actual quantities obtained for one gallon of the water, with- 
= attempting to reconstruct the order of arrangement which we 
et Suppose they had in nature. We found— 
