320 



NOTES AND QUERIES. 



[No. 153. 



is very difficult to cause the free flow of any liquid 

 upon it, and consequently the picture becomes 

 stained. This may be remedied by previously 

 immersing the glass again into the bath, and imme- 

 diately removing it. This is, however, attended 

 with delay, and with increased risk of disturbing 

 the fine collodion film. 



It has been recommended to take the picture by 

 using a bath made of plate glass for the nitrate of 

 silver, and then placing the bath, with the pre- 

 pared collodion glass in it, so that the latter is in 

 the exact focus of the lens ; the bath being so 

 adapted, that the prepared collodion glass will 

 stand exactly on the spot on which the image had 

 been previously ascertained on the ground glass. 

 For large pictures this use of the bath may be 

 desirable, but it possesses no advantages for pic- 

 tures of the ordinary size ; and I believe the light 

 is much slower in its action on the collodion plate 

 than when such plate is not so immersed. 



After the application of the developing fluid, 

 the image sometimes starts out immediately; at 

 other times, two or three minutes may elapse be- 

 fore it fully takes place : and at this period of the 

 operation, it requires some little practice to know 

 to what extent to allow the chemical action to pro- 

 ceed. This can always be readily ascertained 

 ■when the manipulator has the opportunity of re- 

 moving the plate to an open room, by holding a 

 piece of white paper below the picture, because all 

 positives on glass become negatives when seen 

 through. 



The image being perfectly produced, the hypo- 

 sulphate of soda solution should now be applied, 

 which will remove the iodide of silver entirely from 

 all parts which have not been acted upon by the 

 rays of light : and it becomes safe to expose the 

 plate to the open atmosphere, to freely wash it, 

 which, if properly done, renders tlie picture quite 

 permanent. Up to the final period of the opera- 

 tion no washing is requisite : it prevents rather 

 than assists in the necessary chemical action. 



In out-door excursions it is well to have a box 

 adapted so as to pack in the interior space of the 

 camera, formed with groves similar to micro- 

 scopic slide boxes, into which the pictures may be 

 placed after being taken ; and these at leisure may 

 be well protected with a transparent varnish, or 

 painted over with a soft brush with black lacquer. 

 After this, they may be backed with a piece of 

 common black velvet, which forms a perfectly 

 durable protection from any injury. Any of the 

 ordinary transparent vai'nishes may be used for 

 the negatives, when time is not an object; but 

 from such varnishes remaining frequently a long 

 time without becoming hard, I have destroyed 

 many pictures, by too suddenly using them when 

 the surface has appeared hard ; and I therefore 

 recommend the following varnish, which pos- 

 sesses every requisite. It flows over the picture 



most readily, and must be used as the collodion 

 was : — 



Powder two drachms of amber, and macerate it 

 in two ounces of chloroform for two or three days ; 

 shake it often, and filter ofi" for use through thin 

 blotting-paper. The chloroform dissolves a hard 

 resin from the amber, leaving its bituminous com- 

 ponents untouched. This varnish, when well made, 

 very greatly improves all collodion pictures, as it 

 forms on them a delicate coating almost as hard 

 as the glass itself, which effectually protects the 

 picture from all future danger. 



Another varnish may be made by macerating 

 the common amber of commerce in naphtha or 

 benzole. It does not dry so rapidly as the pre- 

 ceding, and has some colour; but where large 

 surfaces are to be covered it is, from its compa- 

 rative cheapness, a desirable coating, as it forms a 

 perfect protection to the picture. 



Postponing for the present any directions for 

 the paper process, or for printing on paper from 

 glass negatives, and trusting that the directions I 

 have already given have been sufficiently explicit, 

 I would again caution the operator to be very 

 careful in observing the greatest cleanliness. The 

 whole process being a series of chemical decom- 

 positions, any of the fluids having accidentally 

 come in contact with the others, that decompo- 

 sition must necessarily have taken place to some 

 degree, which, to be successful, ought only to occur 

 at the moment of operation. 



The hyposulphate of soda being the agent for 

 fixing the picture, which it does by destroying all 

 the iodide, is the one to be especially guarded 

 against, as the slightest intermixture of it with the 

 other chemicals will infallibly spoil them. 



In the after washing of the pictures, if the hy- 

 posulphate of soda is not thoroughly removed, the 

 collodion becomes rotten, and the pictures are 

 soon destroyed by its action. There is no fear of 

 using too much water in washing the picture, so 

 long as it is poured on to the centre of it, and not 

 allowed to wash between the collodion and the 

 glass, by which the film is often torn and removed. 

 Hugh W. Diamond. 



( To he continued. ) 



CURIOUS MISTRANSLATION, ETC. 



(Vol.vi., p. 51.) 



My own cursory reading would enable me to 

 compile a small volume of such blunders ; but 

 confining myself to a very few, I shall adduce the 

 following, because of no remote commission, and in 

 works where least excusable, because the assumed 

 guide of readers. 



In the Foreign Revieiv, No. XLI., under the 

 article of " Memolres sur la Reine Hortense" (the 

 mother of Louis Napoleon), at p. 204., it is stated, 



