260 
NOTES AND MEMORANDA. 
lost Bermuda Tripoli was before me, and its locality discovered. I at 
once communicated my discovery to Mr. Tyson, who was much 
gratified at being the means of leading to so interesting a develop- 
ment ; and as he was about to visit Boston as member of the American 
Association for the Advancement of Science, which was to have its 
sitting in May, my friend offered to take a short note which I hastily 
prepared, together with some of the " new Bermuda earth," and lay 
both before the Academy. Mr. Tyson kept his promise. In the next 
month I received a note from that eminent physician, Dr. Silas 
Durkee, of Boston, of date June 9, 1860, making me acquainted with 
Charles Stodder, Esq., an associate of the Boston Natural History 
Society, and conveying a valuable and detailed catalogue of " the 
genera and species " of Diatomaceae found by Mr. Stodder in the Not- 
tingham earth. I had hardly convinced myself of the identity of the 
" Bermuda Tripoli " and the Nottingham earth, than I thought of my 
friend Mr. J. Sullivant, to whom I dispatched a parcel of the earth in 
question ; and in his reply, dated Juue 4, 1860, he says, " I trust you 
have rediscovered the equivalent of the Bermuda Tripoli." Although 
I had identified the " Bermuda Tripoli " in the Nottingham earth, I 
could not abandon all hope of tracing the former to Bermuda 
Hundreds, on the James. Accordingly, in the summer of 1860, 1 made 
a pilgrimage to the latter place, situated upon the right bank of the 
river, above City Point, about one hundred miles nearly due south of 
Nottingham, and since made remarkable by an historic amphoric 
inclusion, but my visit was without other fruit than a surprise to the 
inhabitants, who failed to appreciate my zeal, but who nevertheless 
very kindly aided my search. About this time my friend Mr. Wm. S. 
Sullivant, of Columbus, sent a portion of the Nottingham earth with 
which I furnished him to Mr. G. Norman, of Hull, as I find in a letter, 
of date January 12, 1861, from Dr. J. M. Dempsey, of Charterhouse 
Square, with this reference : " In the last ' Quarterly Journal of 
Microscopical Science,' there is a short paper by Mr. Norman, of 
Hull, describing the fossil forms of Diatomaceae, contained in a deposit 
forwarded to him by Messrs. Sullivant and Wormley, Columbus, Ohio, 
described or discovered by you at Nottingham, Maryland." The letter 
also contained a request for some of the earth, with which I complied 
at once, forwarding by the same conveyance a parcel to Mr. G. 
Norman, of Hull, and to my almost namesake, the venerable Christopher 
Johnson, Esq., of Lancaster, and included under the cover of each 
several other Maryland deposits. For these, Mr. Johnson wrote in 
acknowledgment a very kind letter, bearing date March 15, 1861, and 
Mr. Norman's reply soon followed, his letter being dated April 12, 
1861. From this time until the present, Mr. Tyson and myself have 
supplied quantities of the Nottingham earth to very many corre- 
spondents ; and upon looking over my own slide of the new Bermuda, 
nothing gives me so much satisfaction as the knowledge that I have, 
by the very probable discovery of the " Bermuda " locality, contributed 
so much to the pleasure of other microscopists. 
The Use of a V-shaped Diaphragm. — At a meeting of the 
Memphis Microscopical Society, on the 21st of January, 1875, 
