MICROSCOPIC PREPARATIONS. ERNEST HINTON, 12, VORLEY ROAD, UPPER HOLLOWAY, LONDON, N. (TWENTY YEARS WITH E. WHEELER.) E. H. begs to inform his friends and the Scientific World that he has commenced business at the above address, and from his long experience with Mr. WHEELER, he will be enabled to submit to their notice a choice selection of newly-mounted Objects in all branches of Nature at the lowest prices. LORD S. G. OSBORNE'S DIATOMESCOPE, Post-free, 12s. See "English Mechanic," August 22nd, page 561. CITY MICROSCOPICAL STUDIO AND GEOLOGICAL MUSEUM, For the Sale of Microscopic Objects, Minerals, Fossils, Rock Specimens, Shells, THOMAS D. RUSSELL, 78, NEWGATE STREET, E.C., MICROSCOPICAL SPECIALITIES, ILLUSTRATING THE GROWTH, REPRODUCTION, AND STRUCTURE OF PLANTS. 1/- and 1/6 each. | Vaucheria in fruit, Batrachospermum and ........ 1/1 each. .... 1/6 Diatoms mounted in monobromide of Naphthaline 1/3", Pediastrum 1/- per slide. ... 1/6 Specially prepared illustrations of Sachs' and Thome's Textbooks of Botany, being copies of Figures in those works. All Post-free.] [Lists on Application. SECOND-HAND MICROSCOPES AND OBJECTIVES. A large assortment by ROSS, BECK, COLLINS, SWIFT, and other first-class Makers, on Sale, very cheap. MICROSCOPIC OBJECTS in great variety. Spécialité Physiological and Pathological Tissues. 500 SECOND-HAND PHOTOGRAPHIC LENSES AND CAMERAS By ROSS, DALLMEYER, TENCH, VOIGTLÄNDER, and all other esteemed Makers. The Cheapest and Best Stock in Londor. New Catalogues gratis on application. Purchases and Exchanges made. Instruments Repaired and Relacquered. SANDS & HUNTER, 20, CRANBOURNE STREET, LONDON. HOW AND CO.'S NEW POCKET MICROSCOPE This Insect is without doubt one of the most beautiful when examined under polarised light. Every muscle can be distinctly seen in the head, tongue, thorax, abdomen and legs, besides showing the striated muscular fibres. LAMP." Very convenient and portable, gives ample Illumination, has all necessary adjustments, is provided with a Cylindrical Case, and can be conveniently carried in the breast coat pocket; when charged with sufficient Oil to burn for above 3 hours, weighs under 12 oz. Price 8s. 6d. Microscopists who are in the habit of exhibiting at the Meetings of their respective Societies and elsewhere, should provide themselves with this little Lamp. MICRO-PETROLOGY, TYPICAL ROCK SECTIONS, 1/6 AND 2/- EACH. JAMES HOW & Co., 73, FARRINGDON STREET, LONDON. J. H. STEWARD, 406 & 66 STRAND, 456 WEST STRAND, 54 CORNHILL, LONDON. WATKINS AND DONCASTER, Naturalists and Manufacturers of Entomological Apparatus and Cabinets. N.B.-For Excellence and Superiority of Cabinets and Apparatus, references are permitted to distinguished Patrons and Colleges, &c. Plain Ring Nets, Wire or Cane, including stick, a/-. Folding Nets, 4/6 and 5/6. Umbrella Nets, 5/6 and 8/- (self-acting). Pocket Boxes,-/6; corked both sides, -/9, 1/-, and 1/6. Ditto, large size, with strap, 6/6. Nested Chip Boxes, 4 dozen, -/9. (black). [box. nor dangerous to use), 1/- per Entomological Pins, assorted or mixed, 1/- per oz. (white or All Articles enumerated are kept in stock, and can be sent immediately on receipt of order. For Sale, a large Assortment of Ova and Pupæ of both British and Foreign Butterflies and Moths. CABINETS.-Special Show Room. The following are the prices of a few of smaller sizes; for measurements and larger sizes see Catalogue (48 pp.) A LARGE STOCK OF INSECTS AND BIRDS' EGGS. Birds, Mammals, &c., Preserved and Mounted by First-class workmen. 36, STRAND, W.C. (FIVE DOORS FROM CHARING CROSS). MAGIC LANTERN AND DISSOLVING VIEWS. The Cheapest and Best House in London for Phantasmagoria, Lanterns, and Dissolving Views, &c. C. BAKER, 243, 2431, & 244, HIGH HOLBORN. Phantasmagoria Lantern, with 3-inch Condenser, will show a disc 10 feet in diameter, with Fountain Solar Argand Lamp, suitable for Schools or Lecturers, £2 17s. 6d. Pair of Ditto, arranged for Dissolving Views, in Case, complete, £7. A New Portable Lantern, Burning Paraffine Oil, with Patent Double Wick Lamp and 3+-in. Condenser, £3 3s. Od., or with Triple Wick, £3 8s. Od. PHOTOGRAPHED SLIDES FOR THE ABOVE. Popular Tales, English or Foreign Scenery, &c. Plain, Is, 3d.; Coloured, from 2s. 6d. each. An improved Lantern with Petroleum Lamp and Forty-eight Views, including a Moving Slide and Chromotrope, from 15s. to 40s. A COLLECTION OF LANTERNS AND VIEWS SPECIALLY KEPT FOR HIRE. CATALOGUES FREE BY POST. MICRO-SLIDES FOR SCIENCE CLASSES. Sale. Mr. PIFFARD'S PATENT COUNTER-SUNK SLIPS are now on Two sizes are ready, 3-16 and 5-8, at 6s. per dozen. They are thus described in the Journal of the Royal Microscopical Society, August, 1884"PIFFARD'S SLIDES.-Mr. B. Piffard has patented a slide, which is made by forming with a diamond a round recess in an ordinary slide. In this the object is placed, and covered with thin glass. The upper surface of the slide is thus perfectly smooth, the cover-glass being even with the slide. There is no danger of the cover-glass and object being knocked off; and the recess causes a very beautiful diffusion of light." REMITTANCE WITH ORDER. ENLARGED CATALOGUE READY, POST FREE. B. PIFFARD, Hill House, Hemel Hempstead, Herts. Possessing all the Properties of the finest Arrowroot, BROWN AND POLSON'S CORN FLOUR Is a Household Requisite of Constant Utility FOR THE NURSERY, THE FAMILY TABLE, AND THE SICK ROOM. NOTE.-Unlike many others, this CORN FLOUR bears the Name of its Manufacturers, who offer the guarantee of their long-established reputation for its uniformly Superior Quality. THE GRESHAM LIFE ASSURANCE SOCIETY. ESTABLISHED 1848. Head Office-ST. MILDRED'S HOUSE, POULTRY, LONDON, E.C. Annual Income FUNDS, 1884. ... Life Assurance and Annuity Funds ... ... ... £3,491,376 £3,391,789 £685,369 Moderate Rates of Premium. Liberal Scale of Annuities. Loans granted upon Security of Freehold, Copyhold, and Leasehold Property, Life Interests, and Reversions; also to Corporate and other Public Bodies, upon Security of Rates, &c. BONUS YEAR, 1885. POLICIES effected before the 1st July 1885 on the profit tables, with annua! premiums, will participate in the Bonus to be declared next year, in the manner prescribed by the regulations of the Society. JOSEPH ALLEN, Secretary. Prospectus, Reports, and Proposal Forms can be obtained on application to the Society's Agents and Branch Offices, or to NORTH BRITISH AND MERCANTILE INSURANCE COMPANY INCORPORATED BY ROYAL CHARTER AND SPECIAL ACTS OF PARLIAMENT. Authorised Capital, £3,000,000. Subscribed Capital, £2,500,000. Paid-up Capital, £625,000. Chairman-JOHN WHITE CATER, ESQ. Deputy-Chairman-CHARLES MORRISON, Esq. Manager of Fire Department-G. H. BURNETT. Manager of Life Department and Actuary-HENRY COCKBURN. Secretary-F. W. LANCE. Foreign Sub-Manager-PHILIP WINSOR. FIRE DEPARTMENT. The Net FIRE FUNDS, irrespective of the Paid-up Capital, now amount to £1,592,235 5s. 2d. LIFE DEPARTMENT. The LIFE FUND now amounts to £3,340,918 11s. 2d. The ANNUITY FUND now amounts to £500,275 17s. lldTHE PRINCIPLES on which this Company is conducted combine the system of Mutual Assurance with the safety of a large Protecting Capital and Accumulated Funds, and thus afford all the facilities and advantages which can prudently be offered by any Life Assurance Office. NINETY PER CENT. of the WHOLE PROFITS is divided among the Assurers on the Participating Scale. The PROFITS are divided every Five Years. POLICIES are INDISPUTABLE after Five Years. ANNUITIES of all kinds are granted. Prospectuses and every Information can be obtained at the Chief Offices LONDON: 61, THREADNEEDLE ST., E.C. WEST END OFFICE, 8, WATERLOO PLACE, S.W. EDINBURGH, 64, PRINCES ST. BRITISH EMPIRE MUTUAL LIFE ASSURANCE COMPANY, NEW BRIDGE STREET, LONDON, E.C. Incorporated under Act 7 & 8 Vict. cap. 110, and further empowered by Special Act, 15 Vict. cap. 53. Accumulated Fund, 1883, nearly £1,000,000 | Profits already Divided £847,000. £1,166,027 NEW SLIDES WORTHY SPECIAL ATTENTION. Type Slide Diatomaceæ. 100 different kinds, all named 21s. Type Slide Foramenifera. 19 different kinds, all named 12s. Most beautiful and elaborate arranged Slides of Diatoms, Anchors and Plates of Synapta, Wheels of Chirodota, &c. For dark ground illumination these are unequalled, each 7s. 6d., 10s., 16s., 21s. Diseased Lung from Coal Miner, Chimney Sweep, Saw Grinder, Gin Drinker, Effects of London Smoke, each 1s. 9d. Jaw of Mole, Horizontal Section. Through all the teeth in situ. W. WATSON & SONS having purchased the Business of Mr. E. WHEELER, Late of Tollington Road, Holloway, including between 40,000 and 50,000 choice specimens, are enabled to offer an unequalled. selection of objects of interest. Either of the above forwarded post-free to any part of the world on application. W. WATSON & SONS, 313, HIGH HOLBORN, LONDON. OPTICIANS TO HER MAJESTY'S GOVERNMENT. ESTABLISHED 1837. N reference to the series of twelve Plates published during the past year, the writer is desirous of thanking numerous correspondents for valuable information. chiefly relating to minute details of structure, and nomenclature; and to reply to suggestions, worthy of consideration, which, if accepted (in some instances), would advance the selection of subjects beyond the scope of "popularity" into the region of biological research. With low powers, and special illumination seeking picturesque effects, many deep and important peculiarities, possibly bearing upon classification, necessarily cannot be detailed or even exhibited; and to enter into intricacies of structure, with higher objectives (as has been proposed), would far outstrip the motive of the work; it may therefore be desirable to repeat that the raison d'être of "Graphic Microscopy" is to encourage the observations of our younger subscribers, in presenting them with an attractive and accurate picture of a distinct subject: simple, popular, easily procurable, and susceptible of artistic treatment. The present example, drawn from life, under moderate amplification, necessarily screening specific character (the same individual furnishing the dorsal and ventral aspect), fairly represents in form and No. 241.-JANUARY 1885. general appearance, a British fresh-water spider-mite, of the Order Acarina, and Family Hydrachnea, of which there are six Genera; four, Arrenurus, Atax, Eylaïs, Hydrachna, the most attractive in beauty; Diplodontus and Limnochares, parasitic and somewhat obscure. The specimen figured is an elegant and lively individual of a form commonly met with: Eylaïs, so designated from collation with published description; the writer, however, was fortunate in the proof of the plate having been seen by Mr. C. F. George of Kirton in Lindsey, whose articles in this journal, on these particular organisms, commencing Sept., 1882, continued at intervals until August 1883, and illustrated with woodcuts "of scientific importance and accuracy, establish a basis of valuable authority on the subject; the number of the eyes in these minute creatures appears to be a matter of important observation, and, as Mr. George remarks, their singular peculiarity and arrangement cannot be overlooked. In the drawing, their position is only indicated; detail would have demanded an amplification so expansive as to have taken the subject beyond the scope of a general view of the entire creature; under deeper examination, four eyes are discovered in pairs, upon the dorsal surface of the cephalothorax, approximating so closely that each pair is seemingly combined in one; even in such minute Acarina these organs possess an ocular power superior to those of insects, and often the appearance of a solitary eye under closer examination is found to be what has been happily termed "helved," the eye projecting on two rounded semi-circles, reniform, a fusion of two stemmata; a divided eye ball. Such a minute condition could not have been shown in a field involving the general aspect of the upper and under sides of the same individual, but it is a peculiarity of significant importance in the decision of species, and upon this point (apart from the portraiture of the specimen), Mr. B |