Nov. 1, 1866.] 



HAEDWICKE'S SCIENCE-GOSSIP. 



259 



different habits to their representatives of the present 

 day; the direction of these borings being not at 

 right angles to, but parallel with, the line of 

 bedding. They are not, I think, mere " worm 

 tracks " analogous to those we find on the last 

 stratum of silt deposited by a recent freshet, or 

 which cross our path in our country walks, after a 

 night's rain. Certainly, their course is quite as in- 

 tricate as the latter, and as difficult to unravel and 

 follow. But here comes another important dif- 

 ference. These "markings " arc iu bas-relief; and 

 a broken line shows, at the point of fracture, a 

 compressed circle. Are they worm " casts " ? 

 They certainly bear some resemblance to the whorled 

 heaps of earth which we see sometimes so Con- 

 spicuous in our gardens. Or, are they still more 

 nearly related to those numerous and beautiful rope- 

 like coils of sand which seem so mysterious to the 

 excursionist, when, for the first time in his life, he 

 walks the wide-spread sea-beach, and which fall to 

 atoms at his touch, leaving him wondering whence 

 they came, and whither they are gone, and what 

 strange law in Nature gave them being without 

 organic structure, and form without flesh, blood, or 

 bone ? Can any of the readers of Science Gossip 

 give me any clue to their ultimate relationships, or 

 refer me to some work where their probable nature 

 and character is described ?—Jas. Meld, Oldham. 



PHOTOGRAPHY. 



A New Process has been announced by Mr. Wil- 

 liam Eirling, of Dorchester, by which a new kind of 

 photograph is produced in porcelain clay. Gelatine 

 plays a conspicuous part in this, as it does in nearly 

 all the photographic improvements more recently 

 introduced.-/. W. W. 



A Necessary Warning.— Mr. Carey Lea has 

 called attention to a source of impaired health 

 amongst photographers not hitherto noticed. All 

 the blame is generally attributed to the fumes of 

 cyanide of potassium ; but when these are got rid of, 

 as they can and always should be got rid of, there 

 still remains an evil not so easily disposed of in the 

 effects of collodion, the ether of -which acts upon 

 the system as a very powerful sedative, and in the 

 course of time lowers the whole tone of the nervous 

 system. In the process of coating a plate, nearly 

 the whole of the ether in the surface of collodion 

 escapes, and the remainder is afterwards given off, 

 from the silver bath in which it is sensitized. The 

 photographer's dark room must therefore be very 

 soon filled with vitiated air, exercising a most 

 injurious influence upon his health. The remedy is 

 in a thorough system of ventilation, by which such 

 mischievous vapours can be quickly and thoroughly 

 carried away.—/. W. W. 



Periscopic Photography. — This name is given 



to a new invention recently introduced in Paris. 

 Two portraits of one person are pasted together 

 back to back, and being placed in the middle of a 

 small angular cabinet, the interior of which is lined 

 with mirrors, combine, so as to give a figure having 

 apparent solidity. At present the published 

 particulars are meagre, but the idea is, if well carried 

 out, a very good one. — J. W. W. 



An Ingenious Contrivance. —The Hon. Mrs. 

 Wood, in her elegantly illustrated little work on the 

 wonders of the microscope, explains a mode of 

 using the eye of a beetle for the purpose of observing 

 the multiplied images of objects which are formed by 

 being passed through the numerous lenses of the 

 eyes of insects. At a microscopical conversazione 

 held at Newcastle-on-Tyne, one of the most attractive 

 objects exhibited was a portrait of Shakspere re- 

 flected through the numerous lenses of a beetle's eye. 

 Eor the purpose of enabling the readers of Science 

 Gossip who have not already tried the experiment, 

 to produce a result analogous, which attracted so 

 much attention, I shall describe as briefly as possible 

 the arrangements necessary to produce the effect. 

 An ordinary microscope, with a £ or J-inch object- 

 glass, is to be placed at an angle of about 45°, and 

 on the stage of the microscope in an ordinary 

 manner, place a well-prepared slide of a beetle's eye, 

 showing the numerous facets. Eocus for the object 

 in the usual manner. Attach to the under side of the 

 stage a kind of box resembling a stereoscope-case m 

 shape, but open at that part in which the lenses of a 

 stereoscope are fixed, the open end to be placed 

 under and close to the stage of the microscope. At 

 the other end of the stereoscopic case, where the 

 obscured glass is generally fixed, place a sheet of 

 glass with the portrait or design intended to be 

 exhibited upon it ; behind the portrait, and at a 

 distance of about two or three inches, place a bull's- 

 eye condenser, and behind the condenser place a 

 lamp ; the object being to throw as much light as 

 possible on the portrait already referred to. Having 

 got the apparatus so arranged, images of the portrait 

 will be formed by each lens of the compound eye of 

 the insect on the stage of the microscope. The 

 images will be a little distance above the surface of 

 the slide, and in order to see the multiplied images, 

 draw the microscope slowly back until the numerous 

 portraits formed through the eye of the beetle enter 

 into the focus of the microscope, and then, instead 

 of seeing the facets of the eye, the observer will 

 perceive the images the illuminated portrait formed 

 by each section of the compound lens within the 

 field of view. Any kind of object may thus be 

 exhibited increased one hundred-fold — portraits, 

 views, chromatropes, &c. ; and thus an endless 

 variety of interesting objects may be introduced to 

 our microscopic soirees during the ensuing winter. — 

 T. P. Barkis. 



