NEW GAS MICROSCOPE.
ANOTHER and greatly-improved hydro-oxygen microscope, whose powers are far beyond either of the two which we have before noticed, has been constructed by Mr. HOLLAND, and is exhibiting its wonder- ful effects at 106, New Bond Street. The instrument at the Micro- cosm in Old Bond Street, and that at CARPENTER'S ill Regent Street, arc nearly similar in the range of their powers ; the only essential dif- ference between them being, that CARPENTER'S is achromatic, and consequently reflects the objects on the disc in purer colours and free from the prismatic hues, which, in instruments not achromatic, are seen forming a fringe or edge round the object. The highest power of these two,instruments is five hundred thousand times ; and they do not show opaque objects, except as colourless shadows, their details of form not being apparent. The magnifying powers of the improved instru- ment of Messrs. HOLLAND and JOYCE extend to two millions and a half,—that is, two millions beyond . the highest powers of the others. It likewise exhibits opaque objects in their natural colours, and with a sufficient idegree of distinctness to render the instrument favailable to the discovery of their exterior construction. But the capabilities of the instrument in this respect are not yet fully developed; the highest power which has been hitherto directed to the display of opaque.ob- jects being thirty-five thousand. Some seeds were exhibited, which appeared like solid objects resting on a dark hackground, or rather sus- pended in space ; those in the centre of the disc being most strongly defined, and producing a sort of chiaroscuro as in one of RsaiSRANDT'S pictures. Experiments are going on with a view to render the powers of the instrument comparatively as efficient for opaque as transparent 'objects.- The disc contains 254 square feet, and is 18 feet in diameter, being twice that of either a the others. The instrument is not achro- matic,.. however. . It exhibited a fflea under the power of 2,500,000, magnified to literally the size of an elephant ; and though only a semi- transparent object, it seemed as vivid and distinct as when seen under a power ofonly 500,000 through the other instruments. There would seem to be no limits to the marvels of the microscope.
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