NATURAL PHILOSOPHY. 139 



M. I'Abbe Laljorde brought under the attention of the French 

 Photograi^hic Society a method which he had adojited to effect the 

 preservation, by photography, of the changeful designs of the 

 kaleidoscope. As a means of preserving patterns for a variety 

 of decorative purj^oses, this application of photography is deserv- 

 ing of attention ; and it may be interesting here to quote from the 

 communication of M. TAbb^ Laborde on the subject. It is worthy 

 of remark, that the method of throwing the designs of the kalei- 

 doscope on a screen by the aid of the magic lantern has since 

 been adopted and exhibited at the Polytechnic Institution : — 



"The variety of designs presented by the kaleidoscope, when 

 turned round, is familiarly known to every one ; yet we are often 

 surprised at the appearance of very curious and unexpected forms 

 which we see disappear with regret. 



"The regular figures which result are depicted on the ground 

 glass of the camera of long focus, and the images are focussed 

 direct without being reflected. This portion is naturally more 

 lighted than the others. It requires several minutes of exposure 

 to obtain a picture on the coUodioned plate. We cannot focus 

 the portions of the image which are several times reflected ; for 

 they appear in the objective as if they came from greater dis- 

 tance : they lack distinctness, and they"^also exhibit the defect of 

 planitude in the mirrors. 



"Notwithstanding these imperfections, I believe I have at- 

 tained the aim I proposed to myself, which is, to place before the 

 eyes of those who are occupied with stained glass, paper hang- 

 ings, and other kinds of ornamentation, very varied patterns, 

 which photograjihy can supi^ly by the hundred." — Photograpliic 

 News. 



PHOTOGRAPHIC PRINTING PROCESS FOR PRODUCING COPIES OF 

 BOTANICAL AND OTHER SPECIMENS. 



A paper, by Mr. Henry Brightman, was read at a meeting of 

 the Bristol Naturalists' Society, December 7, 1865, proposing a 

 ready method of copying leaves, etc. He says: — 



" To lay plants, etc., upon prepared paper, and expose them to 

 sunlight, was a method which had been frequently practiced ; but 

 the pictures so obtained were, technically, negatives, the rej)re- 

 sentation of the object being white, on a dark ground. It oc- 

 curred to the author, that, if these could be rendered transparent, 

 positives might be printed from them. He found, however, that 

 this could be readily done without any previous preparation of 

 the negative ; and he exhibited a number of very beautiful photo- 

 graphs, produced in this way, of ferns, leaves, and even a butter- 

 fly]s wing, showing the wide applicability of the process." Mr, 

 Brightman then described the process in detail ; for the negatives, 

 the albumenized paper should be as thin and free from grain as 

 possible, and sensitized by floating on a sixty-grain solution of 

 nitrate of silver. An ordinary printing-frame was used; but a 

 very long exposure was requisite, especially for positives; and 

 this constituted the chief objection to the process, where many 



