REFLECTING TELESCOPES. One-foot Gregorian Reflecting Telescope on stand, packed in mahogany case, speculum 2 inches diameter.... 6 6 0 One-foot and a half ditto, speculum 3 inches diameter..11 11 0 Two-feet ditto, speculum 4 inches diameter. Ditto ditto, with rack-work motion 16 16 0 .25 4 0 Three-feet ditto, with speculum 5 inches diameter, and rack-work motion ....68 Ditto ditto, with speculum 6 inches diameter, on 42 0 0 0 0 ....105 diameter Ditto ditto, with speculum, 7 inches diameter.. .126 0 Nine-feet ditto, with speculum 9 inches diameter......210 Fig. 253. MICROSCOPES, &c. Gould's Improved Compound Microscope, in case, with apparatus, complete, £1. 15s. This Microscope is recommended to the naturalist, mineralogist, and botanist, for its extreme portability and high magnifying power, being sufficient to discover the most minute animalculæ, seed vessels, &c. It has also the uses of the single, compound, opaque, and aquatic Microscopes. n Fig. 254. Gould's Microscope as set up for use, Fig. 255. Fig. 256. Third-size ditto, with joint for the convenience of slanting the Microscope, containing condenser and 2 silver speculums, £5. 5s. Pillar Microscope, fig. 257, with folding tripod foot, for the convenience of packing; containing Dr. Wollaston's doublet, in addition to the other powers, apparatus, &c. in neat mahogany case, fig. 258. £10. 10s. Fig. 257. Fig. 258. Extra-large very superior Microscope, with tangent screw for very delicate adjustment, moveable stage, 2 condensers, frog plate, Dr. Wollaston's doublet, 2 silver speculums, plain and achromatic lenses, a variety of transparent and opaque objects, apparatus, &c.; the whole packed in a neat mahogany cabinet, price Dissecting Microscopes, very superior.. Small Microscopes with 7s. 6d. Fig. 259. Fig. 261. Fig. 260. 35 0 0 .from 10 10 0 Gardener's Microscope, in case, 7s. 6d. PH& Solar Microscopes, from £6.6s. to £40. Fig. 264. Fig. 267. Cloth Microscopes for ascertaining the number of threads in a given space of linen cloth, in case, 2s. 6d. $ Fig. 262. Flower Microscopes, Fig. 265. croscopes, Fig. 263. Botanical Micros copes, with three powers, 16s. Fig. 266. Magnifying Lenses for the pocket, from 2s. Magnifying Lenses, with 3 powers, which may be used separately or together, from 5s. APPEARANCE OF A DROP OF STAGNANT WATER, AS SEEN THROUGH THE STANHOPE LENS. Fig. 271. metal, 3s.6d. and 4s.6d., fig. 269, 270. Stanhope Lenses, mounted in silver, 6s. and 10s. 6d. This useful and ingenious Microscopic Lens is the invention of Lord Stanhope; both ends are ground convex, the one next the eye rather more so than the other. It has many advantages over the common Lens: for instance, the difficulty of holding the hand steady to the focus, and the loss of light and small field attendant on viewing with a high magnifying power are here obviated; for, the length of the Cylinder being the exact focus, the object has only to be placed upon the end that is ground less convex, or to be brought in contact with it, when the advantage of great magnifying power will be obtained, with a field of nearly five inches-equal to many of the Compound Microscopes. The portability of this Instrument, its low price, and the facility with which it can be used, must recommend it strongly to all who use Microscopic Lenses. With it may be viewed the animalcules in water, mites in cheese, eels in paste and vinegar, the perspiration, human hair, farina and leaves of flowers, the hairs of animals, the down of moths, &c.: and, if a single drop of the crystallization of salts be spread lightly over the end of the Lens, and viewed without delay, the formation of the crystals will be beautifully apparent. Best Silver Stanhope and Coddington Lens, in case.... 1 8 0 for the pocket, particularly adapted for viewing mine- 090 Palmer's Improved Portable Oxy-Hydrogen Apparatus and Microscope with prepared objects, complete. Fig. 274. The Microscope is capable of showing various objects, magnified on a medium of from ten thousand to two million times, price £35.; or, without the Microscope, £20. Fig. 274. E. PALMER begs to submit the following splendid Apparatus to the attention of Lecturers, Schoolmasters, and Scientific Gentlemen, as by far the most portable and convenient Apparatus of the kind hitherto invented. As an Appurtenance to the Laboratory, it will be found exceedingly useful, not only for the production of intense heat and light, but also for many of the manipulations in Pneumatic Chemistry, which usually require expensive Apparatus, large quantities of water; and much room. To the scientific Lecturer it is an Apparatus of great value, as it enables him to exhibit to an audience many very interesting and beautiful phenomena connected with the various Sciences; and also to illuminate diagrams for the illustration of Lectures on Astronomy and Natural History. All danger being obviated by the Gases being kept in separate vessels, which, when charged, contain Hydrogen enough to last half an hour, and Oxygen enough to last one hour, and by simply turning a cock, the Hydrogen vessel may be replenished. Oxy-hydrogen Microscopes, fitted up on a larger scale, from £60. OBJECTS FOR MICROSCOPES. in leather case Set of six ditto, with four transparent objects on each, in leather case.. Set of six glass Slides, with very delicate test objects, in case... .. 0 18 Set of 40 glass Slides, each containing a different object, in leather case.... Set of 50 ditto, arranged in different partitions, in maho gany case.. Set of six double glass Slides, containing 18 sections of the following woods, oak, ash, elm, willow, beech, and horse-chesnut, in case ... Set of twelve ditto, with 36 sections, each slide containing three different cuttings Set of six glass ditto, containing specimens of sea-weeds and botanical objects, in case Set of six ditto larger, with a great variety of objects, in case Set of 12 ditto larger, for Solar or Oxy-hydrogen Microscope, in case 0 Set of six Objects preserved in Canada Balsam, in case.. 0 12 Large Balsam Objects, for Solar and Oxy-hydrogen Micro- 1 1 0 Sections of Fossil Woods for the Microscope...... each 0 4 0 These sections are cut so thin, that they readily transmit the light through them, and show the form and disposition of the woody fibre, vascular tissue, medullary rays, glands, pith, &c. &c. POLARIZATION OF LIGHT. Fig. 275. Apparatus to show the beautiful and extraordinary phenomena of Polarized Light, upon an opaque or semi-transparent screen, consisting of brass work with condensing lenses, and a polariscope, with tourmalines and series of different crystalline polished plates in ivory slides. By the light obtained in the combustion of lime with oxy-hydrogen gas, may be exhibited on a screen the splendid coloured rings, &c., £9. Polariscope, in rosewood Polarizing Eye Pieces.. 0 5 0 Double Image Prisms, of calcarious spar and glass...... 0 10 0 |