120 = On Fossil Infusoria, discovered in Peat-earth, 
it may in some cases have been confounded with marl, from 
which its action with acids would distinguish it. To examine for 
the Infusoria, diffuse a small portion in a drop of water, and exam- 
ine with a microscope of high power. ‘The very convenient 
Raspail Microscope is well suited for the purpose, but to see the 
fine lines on these shells most distinctly, a small glass sphere made 
according to the method of Torre of Naples, should be used with 
the Raspail fixtures.* 
As I have not had the good fortune to obtain Ehrenberg’s 
papers on Recent and Fossil Infusoria, I am unable to give the 
names of the species occuring at West Point. I have, however, 
made sketches of the principal forms occuring in the peat-earth, 
which I hope will serve to make these singular beings more gen- 
erally known and perhaps also enable those who have Ehrenberg’s 
papers, to identify our species. All the Infusoria figured on 
2, occur abundantly in company with the Closteria, and 
poveral other forms, in a living state, in the waters near the deposit 
of fossils. Fig. 5, represents the species which appears most 
abundant as a recent species, and Jeast abundant as a fossil. 
As the species of Algee known as the Diatome, have also a si- 
liceous shell and occur abundantly in our ditches, &c. ina recent 
state, and occasionally in the peat-earth in a Sonail state, and as 
ee obscure but beautiful tribe appears to have been wholly neg- 
not even menses. the origin of this. ‘sedimentary accu accumulation, w Pano Prenils 
occurs under circumstances which afford no clew to its source. I have 
forgotten all the localities whence the specimens were obtained, which were oad 
_ into'my hand by various individuals some years since, some of whoin supposed it to 
be magnesia and others porcelain earth.” 
_ *I make these spheres by drawing into a thread a portion of green glass (flint glass 
will not answer, as the lead reduces,) and then snapping off a portion, about half a 
line or a line in length, I lay it upon a fragment of charcoal and very carefully 
that the bit of glass has assumed the spherical form, (otherwise ashes adhere, and 
the glass becomes full of flaws.) The spheres are then easily set in lead, thus: 
Make a conical depression in a piece of sheet lead and perforate the apex of the 
cone with a hole somewhat less in diameter than the glass to be set. The glass 
is then to be forced into the hole so as to project through slightly. I have fre- 
quently made, and set in five minutes, spheres in this manner, which would 
agnify from one hundred, to four or five hundred times the diameter of the object. 
Such glasses are much superior to any usually kept for sale in this country. 
sume that these glasses would have been more used, had they been tried with the 
proper aiieencaee for light. With the beautiful fixtures of the Raspail Micro- 
a Be es Sed little to be wished for, eat with regard to — or 
