116 



NOTES AND QUERIES. 



[No. 170. 



ing, be the 24th of February in common years, 

 ami the 25th hi leap-years: therefore, the super- 

 numerary or superfluous day, added on account 

 of leap-year, was considered to be the 24th of 

 February, and not the 25th ; which latter, in those 

 years, became the true " Sixth before the Kalends." 

 Indeed, it is highly probable, although it cannot 

 be supported by direct evidence, that the first day 

 of the double sextile was distinguished from its 

 name-fellow of the following day by having the 

 word "bis" prefixed to sextum; so tiiat, in leap- 

 years, the 24th of February would be expressed 

 as follows : " Ante diem bis-Vl Calend. Martias;" 

 while the following day, or the 25th of February 

 (being considered the real Simon Pure), Avould 

 retain the usual designation of " a.d. VI Calend. 

 Mar." Such an hypothesis offers a reasonable 

 explanation of the seeming reversal in terms of 

 calling the day which Jirst arrived posterior, and 

 that which succeeded it prior. 



Althougli the Church of England Calendar now 

 places the feast of Saint Mathias invariably on the 

 24th of February in all years, yet the earlier copies 

 of the Book of Common Prayer allocated it to 

 " The Sixth of the Kalends of March," without 

 any direction as to which of the two days, bearing 

 that name in leap-years, it should be appropriated. 

 The modern Reformed Church Calendar tiierefore 

 repudiates the usage of the Romans themselves, 

 rather than that of the Roman Catholics. A. E. B. 



Leeds. 



PHOTOGRAPHIC NOTES AND QUERIES. 



Portable Camera for Travellers. — Yonr corre- 

 spondent E. S. asks for a clear description of a 

 camera that will supersede the necessity of a dark 

 room. Mr. Stokes has invented one ; and in the 

 early part of the photographic exhibition at the 

 Society of Arts it was exhibited. The weight of 

 the camera is only nine pounds, including focus- 

 sing-glass, lens, shutter, &c. The shutter is so ar- 

 ranged that it will contain from twelve to twenty 

 pieces of prepared paper, each piece between 

 separate sheets of blotting-paper. Light and air 

 are completely excluded, by the paper being 

 pressed by the front portion of the shutter. When 

 required for use, the first piece of paper is placed 

 at the back of the glass. By the assistance of a 

 small hood, the impression is then taken ; and, by 

 removing the millboard, the paper will fall back 

 into its place. At the same time another piece can 

 be brought forward, ready for a second picture, 

 before focussing, and so on to the end. The hood 

 is made of India rubber cloth, and answers the 

 purpose of a focussing cloth, without the trouble 

 of removing it from the camera throughout the 

 day. The size of the pictures that can be taken 

 by it is 9 J by 12 inches. It has been tried during 



the latter pai't of the last year, and proved most 

 successful. Philip H. Delamottb. 



Baj'swater. 



The Albumen Process. — I shall be greatly 

 obliged to Dr. Diamond, or any other photo- 

 grapher, by their kindly communicating through 

 your medium their experience with albumenized 

 glass. I have Thornthwaite's Guide to Photography. 



I should like answers to the following Queries : 



Must tlie albumen be poured oif from the plate 

 after it is spread over the surface, in the same 

 manner as collodion ? 



Is the plate (while roasting, according to the- 

 process of Messrs. Thompson and Ross) nearly 

 perpendicular in the process ? 



Will the iodized albumen, for giving the film, 

 keep ; and how long ? 



How long will the plate retain its sensitiveness 

 after exciting? 



May the same sensitive bath be used for a 

 number of plates without renewing, in the same 

 way as silver bath for collodion ? 



In conclusion, what is the average time with 

 single achromatic lens, six or seven inch focus, to> 

 allow to get a good picture ? 



Will photographers who are chemists turn their 

 attention to obtain sensitive dry glass plates ? for 

 I think there can scarcely be any <loubt of the 

 advantage of glass over paper for small pictures 

 (weight, expense, &c., are perhaps drawbacks for 

 pictures larger than 5x4 inches) ; but the desi- 

 deratum is a sensitiveness nearly equal to collo- 

 dion, and a plate that can be used dry. 



Thos. Lawrence^ 



Ashby-de-la-Zouch. 



Black Tints of French Photographers. — Can 

 you inform me, through the medium of your valu- 

 able periodical, how those beautiful black tints, so- 

 much prized in the French prints from photo- 

 graphic negatives, are obtained? By so doing 

 you will give great pleasure to several excellent 

 amateur photographers, and especially your con- 

 stant reader, Philophotog. 



Originator of the Collodion Process. — As some 

 think the credit of the invention of the collodion 

 process a matter of dispute, will you allow me to 

 remind your correspondents that the truth will be 

 much easier to discover if they will confine them- 

 selves to actual facts? 



In No. 167., p. 47., G. C. first recklessly accuses 

 Mr. Archer of untruth, and then tests his own 

 claim to truth by quoting from Le Gray's edition 

 of 1852, to prove Le Gray's edition of 1850. Why 

 did he not go back at once to the 1850 edition; 

 and if that contains anything like an intelligible 

 process, why is it altogether omitted from Le 

 Gray's edition of 1851, which was the one Mb. 

 Archer spoke of, and correctly ? 



