1865.] Physics. 127 



of this instrument, which will set microscopists wondering, is Mr. 

 Tolles, of Canistota, New York, long favom-ably known by the great 

 excellence of his objects for the microscope and. telescope, who, it is 

 said, has advanced one step farther than Mr. Wenham. The writer 

 of the notice by no means wishes to depreciate Mr. Wenham's inven- 

 tion, so freely made public, and undoubtedly the best hitherto devised ; 

 but with the new binocular eye-piece, and an objective of two-thirds, 

 there was a marked difference in the definition by reflected and direct 

 vision. The division of the pencil is effected so far from the objec- 

 tive, that the interference with definition is a minimum. The tubes 

 are symmetrical and parallel, and are adjusted for different eyes by a 

 screw and milled head, giving a range much greater than can ever be 

 required ; and no alteration is required for the adaptation of the eye- 

 piece to any microscope, as it is used in precisely the same manner as 

 the ordinary eye -piece. It lengthens the microscope, however, about 

 four inches, though not necessarily so much. The eye-piece, with its 

 present arrangement, is a first-class erecting one, giving with the 

 various powers, up to four-tenths, full and clear fields, beautifully 

 illuminated by the mirror alone, and without any special trouble with 

 the higher powers, as is the case with Mr. Wenham's arrangement. 

 The writer speaks rapturously of the appearance presented under the 

 new eye-piece by such objects as Aulacodiscus Petersii, transparent 

 injections, living Diatoms and Desmids, &c, but he declares that he 

 is not at liberty at present to explain the principle upon which Mr. 

 Tolles has been enabled to divide the pencil so far from the objective, 

 but he declares it to be theoretically, as well as practically, correct, 

 though it is so simple that he wonders that it did not at once occur 

 to those eminent European opticians, who have devoted so much time 

 and skill to the perfection of the binocular arrangement. The eye- 

 piece works well when applied to the telescope, but the stereoscopic 

 effect is not equal to that produced when applied to the microscope, 

 owing to the small angle of the object-glass. 



Mr. Chadburn, optician of Liverpool, has patented a new Oxy- 

 calcium Lantern, which throws enlarged images of opaque objects on 

 a screen, the same as the magic-lantern projects transparent ones ; so 

 that with it ordinary prints, photographs, sketches, drawings, diagrams, 

 &c, are delineated with all their colours. Coins, medals, relievos, &c. 

 are shown with the same accuracy. The effect produced by exhibiting 

 a watch face with hands moving is very striking. Coloured cartes de 

 visite have all the charm of oil paintings. In this particular, the in- 

 strument will be of great service to the artist, for he will be enabled 

 thereby to throw enlarged pictures upon his canvas to any proportion, 

 and follow every lineament with the pencil, without having the trouble 

 of photographic manipulation on so large a scale. The instrument 

 is most simple in its construction and management. The light used is 

 the oxy-hydrogen. The rays from the lime cylinder, which is placed 

 in the centre of the box, are received upon a large concave mirror 

 and reflected to a 9-inch condensing lens, which concentrates the light 

 upon the object to be enlarged ; and this object is placed at an angle 

 of about 45° to allow of the object-glass (double acromatic combina- 



