( 13 ) 
SWIFT & SON’S New 1/12 in. Homogeneous Immersion Objective of 
1'25 N.A., in which the New Abbe-Schott glass is used, price £5 5s. 
This lens, Swift & Son guarantee to be equal to any other Homogeneous Immersion 
Objective of the same N.A. 
Swift & Son are continually receiving testimonials in praise of the above Objective. 
A New 1/12 in. Apochromatic Homogeneous Immersion Objective of 
1-4 N.A., £16. 
Compensating Eye-pieces, magnifying 10, 20, and 30 times, price 
each, £2. 
These Eye-pieces also give excellent results with Objectives made with the old Media. 
Projection Eye-pieces for Photo-Micrography, magnifying 3 and 
6 times, each £2. 
For 'particulars of Professor CrooJcshanlc’ s Bacteriological Microscope^ and Medical 
Press Comments, send for Circular. 
Y 03PTIOYL 
81, TOTTENHAM COURT ROAD, LONDON, W. 
MICROSCOPIC ROCK SECTIONS. 
Pikrite, Serpentine, Lherzolite, Gabbro, Dolerite, Basalt, Diabase, Tachylite, Andesite, 
Porphyrite, Diorite, Trachyte, Phonolite, Syenite, Rliyolite, Pitchstone, Granite, Lavas, 
Ashes, Gneiss, Schist, Slate, Limestone, Quartzite, &c., &c.. Is. 6d. each. 
How’s Microscope Lamp, 12s.; How’s Pocket Microscope Lamp, 8s. 6d, 
JAMES HOW & CO., 73, FARRINGDON STREET, LONDON. 
F. H. BXJTILiER (M!.Y. Oxon., Assoc. S, Mines), 
NATURAL HISTORY AGENCY, 148, BROMPTON ROAD, LONDON, 
Supplies MICRO. -GLASS, of the best English make only, as under: — 
SLIPS, per gross: — Crown, ordinary, 3" x I", 3/6; do., thin, 5/-; Patent Plate, ordinary, 4/6, or with 
cavities, 11/- ; do., extra white, 7/6 ; do., ordinary, 3" X H”, 6/- ; do., 3" X 1^", 7/-; do,, 3^" X 
per dozen, 2/6. 
COVER GLASSES, No. 2 thickness, per oz. Circles, to -/,/' diam., 5/6 ; from f" diam. upwards, 
4/6 ; Squares, i" to 4/6 ; from i" upwards, 3/9 ; Rectangular, 1" X i", 1y%" X i", If" X If", 
If" X 1|", 2f" X r, 3/9. 
In the employment of the above no waste is to be apprehended from defect in material, colour, or 
workmanship. The new micro, watch-glasses for biological use always in stock. 
ROCK SECTIONS from carefully selected and localized examples, of large size and specially 
prepared for petrographical ivork by the most experienced hands, 2/- each. Inspection invited. Hand 
specimens can usually be provided with the sections. Rocks and minerals cut and polished on the premises. 
Rack-boxes. 
ADVERTISEMENTS FOR THE JOURNAL. 
li./L'Fi. JOrnST NTVIvd:. 
20, HANOVER SQUARE, W., 
Is the sole authorized Agent and Collector for Advertising Accounts 
on behalf of the Society. 
