NOTES AND QUERIES. 67 
On the other hand it is only right that we should expect a guéd 
pro quo, and it is a fact that in several districts where both Presi- 
dent and Secretary are upon our free list, we have not a single 
subscriber. 
Surely every subscriber upon our books at present is acquainted 
with at least half-a-dozen other Microscopists, is it too much to 
ask them to try to secure half of them as subscribers to us? We 
thank those Secretaries whose exertions on our account have borne 
such good fruit. 
PHoto-MicrocapHy.—In our next issue will appear a paper 
upon photo-micrography, illustrated with a Woodburytype perma- 
nent enlargement of the proboscis of the blow-fly, and several 
woodcuts, It should have appeared in the present number, but 
we had miscalculated the time necessary for the production of a 
Woodburytype picture. 
MouUNTED SLIDES.—We have lately received several very good 
slides of P. Angulatum from Mr. J. T. Norman, and four splen- 
didly cut sections of Lichens from the Rev. W. Johnson, of 
Whitehaven, consisting of Graphis elegans, Physcia stellaris, Col- 
lema pulposum, and Nephromium lusttanicum, in all of which the 
details are very clearly shown. 
Damar Mountinc Mepium.—What is the correct formula for 
this medium which is now used so much in lieu of Balsam ?>— W. 
CEMENT FOR GLYCERINE Mounts.—What is the best cement 
for sealing covers of objects, mounted in glycerine, without a cell? 
—W. 
Dark GrRounpD ILLuMINATION.—Is there any simple method 
for obtaining dark ground illumination without special apparatus ? 
—W. 
RE-uUNIoN.—On Saturday, Feb. 5th, a re-union of past and 
present members of the Manchester Field Naturalists Society took 
place at the Trevelyan Hotel, Corporation Street, Manchester, to 
celebrate its 21st anniversary, and also to do honour to the founder, 
Mr. Leo H. Grindon. A large number of ladies and gentlemen 
were present. 
MANCHESTER SCIENTIFIC STUDENTS.—The syllabus of the fortieth 
session has just been issued to the members. On the opening 
night, a microscopical conversazione was held. The lectures for the 
session are—Messrs, A, Duncan, on pure air; Hastings C. Dent, 
on the ethics of science ; T, Armstrong, F.R.M.S., on some modern 
