On the Accelerating Process of Daguerreotype Operation. 215 



If the use of paper should continue to be preferred, I would 

 advise the coating of it with one or two layers of starch or 

 albumen, and then we should have the same distinctness of 

 the impression as in the proofs made with iodine ; but I believe 

 that, with regard to photography, paper will never be equal 

 to a hard and polished body covered with a sensitive layer. 

 I may add that very beautiful positive impressions may be 

 made upon opaline glass. . 



May we not hope by this method to take impressions trom 

 lithographic stones, even if the copied impression had to be 

 drawn in chalk, if it cannot be done with any other kind ot 

 inking? I have obtained very beautiful impressions upon a 

 ic/n'^f (hone-stone) coated with a layer of albumen. By this 

 means, engravers upon copper and wood will be able to obtain 

 impressions, which it will be very easy for them to work upon. 



XXXII. Question of Priority respecting the Discovery ^ 

 the accelerating process in the Daguerreotype operation. By 

 A. Claudet, Esq. 

 To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 



I HAVE lately heard that Mr. Goddard knew as tar back as 

 the year J 840 that bromide of iodine was more sensitive to 

 light than iodine alone in the Daguerreotype process; and that 

 a short letter merely mentioning the fact written by him was 

 inserted at the time in the Literary Gazette, 12th Dec, 1840. 

 Havinw myself until now had all the honour of the discovery 

 of the accelerating properties of chlorine and bromine com- 

 bined with iodine, I am happy to be the first to bring Mr. 

 Goddard's claim before the public, who will have to bestow on 

 him the share of merit for what he has done prior to my com- 

 munication to the Royal Society, which was read at the meet- 

 in^ of the 10th of June 1841. I have acted openly. Alter 

 ha^'ving made my communication to the Royal Society, 1 made 

 the same to the Academic des Sciences the 22nd of the same 

 month, and my discoveries have been mentioned in all the 

 treatises on photography; and until now, neither Mr. God- 

 dard nor any other person has yet contested publicly that 1 

 was the first inventor of the accelerating process in the Da- 

 guerreotype operation. , , , , • 



It is strange that Mr. Goddard's letter should have been 

 unknown and unnoticed by all writers on photography either 

 Kn.dish or foreign. If Mr. Goddard had found the means to 

 uvaTl himself with certainty of the properties ot bromide ot 



