Monthly Microscopical 
58 PROCEEDINGS OF SOCIETIES. Tournal, July 1, 1870. 
to learn that the following thickness of glass has been used for covers 
of objects :— 
Objective. Alone. With Searcher. 
3th objective. | =22,ths, or 06 inch. +i4,ths, or *074 inch. 
ith dry. | s28,ths, or °018 ,, =24,ths, or *024 ,, 
4th immersion. | 29, ths, or -020 ,, 724 ths, or “024 ,, 
zath dry. sopoths, or *007 _,, adooth, or 010 ,, 
I have the honour to remain, with great respect, 
Yours very faithfully, 
Rey. J. B. Reape. F.R.S., P.R.M.S., G. W. Royston-Picorr. 
&e., &e., &e. 
Postscript.*—The newly-constructed 1th Powell and Lealand 
(both dry and immersion) I am happy “to add, show diminished 
spherical and chromatic aberrations. Up to May last considerable 
residuary errors could be detected in all the best glasses in use. 
Last year Messrs. Powell and Lealand effected so much improvement 
in my favourite 1th as to name it a very fine glass. But in com- 
parison with it I have no hesitation in declaring that the effect of 
their new combinations is simply superb. The difference between the 
new glasses and the old sufficiently justify all the criticisms in which 
I have ventured to confidently assert the existence of unsuspected 
residuary aberration in the finest objective of last year, notwithstanding 
the bold denial they have received. 
Donations to the Library from May 11th to June 8th, 1870 :— 
From 
Land and Water. Weekly : sit (yl teen Vee eterna: 
Society of Arts Journal. Weekiy ej) ait) fae) ale ee OUREEDaE 
Nature. Weekly doc ae oe (een deta eee Taare 
Scientific Gain "Part VIL oa. sees wen. ni 
Quarterly Journal of the Geological Society ae .. Society. 
Transactions of the Royal Trish, Academy. 8 Parts ., Academy. 
Medical Progress. By Dr. L.S. Beale .. .. . .. Author. 
Canadian Journal. Vol. XII. No. 5. 
; : Brighton and Sussex 
Moss Flora of Sussex. ByC.P.Smith .. .. .. « { Natale tae ee ee 
Journal of the Linnean Society : os ot SeOCTELY 
Microscopical Anatomy of the Human Liver. By Dr. 
H. D. Schmidt .. .. «. «oe Author, 
Philosophical Transactions. Vol. CLIX. " Part 2 .. President. 
, The following gentlemen were elected Fellows of the Society :— 
Thos. Lancaster, Esq. 
Chas. J. Morgan, Esq. 
Chas. C. Capel, Esq. 
and 
James Hankey, Esq., of Chicago, an Honorary Fellow. 
Watter W. REeEves, 
Assist.-Secretary, 
* Added June 25th, as the Journal goes to press.—Ep. M. M. J. 
se fe ee 
