Messrs. Sullivant and Wormley on the Stri@ of Diatoms. 249 
The sulphuretted hydrogen of the Lafayette water is equal in 
quantity to that ingredient in the Greenbrier White ceed 
water of Virginia, and varies as in that water. I established this 
t by many and careful sulphur determinations of the Lafa- 
yette water by the chlorid of arsenic test upon water taken at the 
spring. Ihave also made frequent careful density determina- 
tions of the water during a period of six months, and have 
found the specific gravity invariably to the third decimal point, 
proving an invariable mineral composition for the water during 
that time. 
The Lafayette water has been used with great success in the 
diseases for which sulphur waters are applicable. 
I have noticed in the neighborhood of this city several chaly- 
prings. A very fine one is situated upon the shore of 
Barnett’s creek, which flows through the celebrated battle-ground 
of Tippecanoe at a distance of seven miles from Lafayette. The 
temperature of the water was 53° when that of the air was 84°. 
It strikes a dark color with extract of galls, has a strong chaly- 
te taste, and coats the stones over which it flows with an 
ochreous deposit. 
Art, XXX.—On the Measurement of the Strie of Diatoms; by 
W.S. Sunurvant and T, G. WORMLEY. 
No characters are so constant for distinguishing the species of 
diatoms as those drawn from the strise on their frustules. The 
. Attention appears to have been first directed to this subject 
in Silliman’s Tonenal for 1849-50, by the late distinguished Pro- 
tJ. W. Bailey of West Point, and Mr. De La Rue of Lon- 
