SCIENCE- G OSSIP. 



117 



CONDUCTED BY B. FOULKES-WINKS, M.R.P.S. 



EXPOSUKE TABLE FOR SEPTEMBER. 



The figures in the following table are worked out for plates of 

 about 100 Hurter & Driflaeld. For plates of lower speed number 

 give more exposure in proportion. Thus plates of 50 H. & D. 

 would require just double the exposure. In the same waj', 

 plates of a higher speed number will require proportionately 

 less exposure. 



Time, 10 a.m. to 2 p.m. 



Between 8 and 10 a.m. and 2 and 4 p.m. double 



the required exposure. Between 7 and 8 a.m. and 



4 and 5 p.m. multiply by 4. 



Subject 



F. 5-6 



F.8 



F.ll 



F.16 



F.22 



F. 32 



JL 



F.45 



F.64 



i 



Sea and Sky . . 



Too 



T50 



Tio 



io 



i^ 



i 



Open Landscape 

 and Shipping 



M. 



j_ 



h 



^ 



i 



i 



I 



1 



Landscape, with 

 dark fore- 

 ground, Street 

 Scenes, and 

 Groups 





JL. 



i 



I 



i 



1 



2 



4 



Portraits in 

 Kooms 



V 



4 



8 



16 



32 



- 



- 



- 



Light Interiors 



4 



: 8 



16 



32 



1 



2 



4 



8 



Dark Interiors 



16 



, 32 



1 



2 



4 



8 



16 



30 



The small figures represent seconds, large figures minutes. 

 The exposures are calculated for sunshine. If the weather is 

 cloudy, increase the exposure by half as much again ; if gloomy, 

 double the exposure. 



The Royal Photographic Society. — The 

 forty-sixth annual exhibition will be held at the 

 New Gallery, Regent Street, London, W. There 

 will be a private view from 11 a.m. to 4 p.m., and 

 a Conversazione at 8 p.m., on Saturday, September 

 28th, to which members and exhibitors will be 

 invited. The Exhibition will be open to the public 

 on Monday, September 30th, and will close on 

 Saturday, November 2nd. Professional members 

 and others are invited to make prompt application 

 for space should they desire to exhibit in Section 

 II., which is devoted to general professional work. 

 Particulars are given in the prospectus already 

 issued to members, and a plan of the space set 

 aside for this section, with further details, may be 

 had upon application to the Secretary at 66 Russell 

 Square, W. 



Practical Tricolour Photography. — At the 

 meeting of the Royal Photographic Society, held 

 on May 28th, 1901, Mr. Howard Farmer read a 

 paper upon this subject having exclusive reference 

 to the special application of tricolour photography, 

 in which typographic screen blocks are used as 

 the method of printing. The paper deals very 

 fully with the whole process of three-colour work, 

 and practical working detail is given : the lecture 

 is printed in the Society's Journal for June 1901, 



and may be had upon application to the Secretary 

 at 66 Russell Square. This paper was followed by 

 a further lecture by Mr. Howard Farmer upon 

 " The Optics of Tricolour Photography," in whicb 

 the lecturer traced the history of colour photo- 

 graphy from principles laid down by Professor 

 Clerk Maxwell in 1860, contained in the Trans- 

 actions of the Royal Society, under date of January 

 1860, with the title " The Theory of Compound 

 Colom-s," and for which the Society awarded the 

 Professor the Rumford Medal. After touching 

 upon the various processes of Clerk Maxwell,. 

 Monsieur Louis Ducos du Hauron, Monsieur Chas.. 

 Cros, Professor Vogel, Baron Hiibl, and Mr. 

 Frederic Ives, the lecturer gave a very clear andl 

 interesting description of the whole system of 

 tricolour photography, comparing the various pro- 

 cesses and proving beyond doubt that the honour 

 of first explaining the theory of three-colour photo- 

 graphy and its practicability rested entirely with 

 Professor Clerk Maxwell. 



Photography in Morocco.— The latest convert 

 to the pleasures of the camera appears to be no 

 less a personage than the Sultan of Morocco. We 

 understand that he has developed such a keen 

 interest in everything photographic that he now 

 possesses many cameras, both for hand and stand,, 

 of various types. Even this, however, was not 

 sufficient to satisfy His Majesty. After a recent 

 examination of two of the most marvellous photo- 

 graphic instruments ever produced, we were in- 

 formed by Messrs. Adams & Co., of Charing Cross 

 Road, London, that they were instructed by the 

 Sultan to make two of their " De Luxe " cameras •,. 

 one in 18 carat gold, quarter-plate size, and one in 

 silver, half -plate size. The instructions were that 

 they should be the finest instruments that it was- 

 possible to produce in every way. The cameras 

 were fitted with Ross-Zeiss lenses of two foci. 

 They were made of the finest seasoned mahogany 

 and beautifully polished, covered in brilliant red 

 morocco, and all the metal was gold in the one 

 case and silver in the other, each piece of metal 

 •being most beautifully chased. Both cameras were- 

 supplied with carrying cases of white morocco 

 leather, velvet lined, gold corners and locks. It is. 

 stated that the total cost of these two cameras was 

 £3,000. The Sultan is, we hear on authority, 

 a very good photographer, and it was only 

 a few days since that a celebrated lady traveller 

 (Mrs. Isabella Bishop) was relating to us her ex- 

 perience a few months ago at Fez, when the 

 Sultan exhibited to her his achievements in photo- 

 graphy. Mrs. Bishop is herself a very clever 

 amateur in the art, and has brought back with her 

 some interesting souvenirs of her visit. 



PHOTOGRAPHY FOR BEGINNERS. 

 By B. Foulkes-Winks, M.R.P.S. 



(^Continued from page 85.) 



Section I. Cameras (contimied). 



Foldpkg Hand Cameras.— This type of hand 

 camera has been introduced to a large extent 

 from America, and the illustrations we show will 

 serve as a good example of this style of instrument. 

 They are generally supplied with dark slides, and 

 are made to use either in the hand or upon a tripod. 

 The front, carrying the lens and shutter, is made 

 to push laack into the body of the camera and 

 base-board. These fold up, fprming a neat leather- 



