Feb. 19. 1853.] 



NOTES AND QUERIES. 



187 



iron I have stated, diluting the solution more ; 

 then was compelled to diminish the quantity to 

 twelve grains, and now I use eight. I have tried 

 the proportions recommended by French photo- 

 graphers, but they seem to contain too large a 

 proportion of iron. I prefer the use of the proto- 

 sulphate to the protonitrate of iron from Its cheap- 

 ness, and the ease with which it is made up. It 

 will also keep for any length of time, rather im- 

 proving than otherwise. 



I back with liquid jet from Suggitt, opposite the 

 House of Correction, Mount Pleasant, Clerkenwell. 

 It dries rapidly, and brightens the appearance. 



G. H. P. 



Mr. Weld Taylor's Iodizing Process. — The pro- 

 cess I sent to your columns last month, for iodizing 

 paper, is applicable only to the paper of Canson 

 Freres; and I may further explain, that if the 

 solution does not answer well, it may be washed 

 over again with a solution of iodide of potassa 

 only of the usual strength, and then set on a dish 

 of slightly-acidulated water, to assist the separa- 

 tion and set free the potash. To make the mat- 

 ter clear to Me. Shadbolt, I may observe, to 

 one who is in the habit of iodizing paper, a con- 

 siderable amount of the passage relating to cyanide 

 of potassa could not be misunderstood ; the nitrate 

 of silver being added to the iodide of potassa, 

 forms at once a precipitate which it is required to 

 take up. The old double iodide says, add iodide 

 of potassa till it does so, and it will do so ; but the 

 cyanide of potassa does it much better, and the 

 cyanogen is lost as the paper dries, otherwise it 

 would take no image at all. In the process I gave 

 it merely requires an equivalent, " and cyanide of 

 potassa is always of use in many of these pro- 

 cesses." That equivalent is of course best arrived 

 at by a solution, as, if the cyanide of potassa were 

 added in the lump, it would be lost or be in 

 excess. 



Further, I may enlighten Mb. Shadbolt by 

 assuring him that the iodizing paper with the 

 ammonio-nitrate of silver, which I never saw 

 published yet, is the best way ; and I may con- 

 fidently assert that the better ways of iodizing 

 papei's are not published at all. It is a tedious 

 process to do, but it is as certain as taking a posi- 

 tive from a negative. At present I have not 

 space to give my way of doing it. I may also 

 add, that it will not answer with all papers. In 

 fact, all samples of paper require some modifi- 

 cation of the process, as the chemicals are differ- 

 ent in the various modes of bleaching paper by 

 different manufacturers. The ammonio-nitrate is 

 perfect with Whatman's paper ; indeed it is a sub- 

 ject of much regret, that this maker has not turned 

 out a paper as thin and hard as the Canson Freres. 

 The latter gentlemen have added some chemical, 

 probably iodine, to their paper, which renders it 



almost impossible to iodize it at all. I believe it 

 to be iodine, because the paper becomes perfectly 

 black over free iodine, which no English paper 

 will do. At all events, this paper is very uncer- 

 tain, although it has a quality in appearance that 

 is unsurpassed by any other. Weld Tatlob. 



7. Conduit Street West, Bayswater. 



Sir William Newton's Process: Further Ex- 

 planations. — In reply to your correspondent 

 F. Maxwell Ltte, who is desirous of knowing 

 my motive for washing the paper over with 

 chloride of barium previous to iodizing — 



In the first place, I find that it appears to give 

 strength to the paper. 



Secondly, that the action in the camera is better 

 and more certain. 



Thirdly, it keeps cleaner in the bringing-out 

 process, thereby allowing a longer time for a more 

 complete development. 



Fourthly, I have never found any solarizing 

 take place since I have used it (about three 

 years); and, fifthly, I find that it keeps longer 

 and better after it is excited for the camera. 



From the observations which I have made since 

 I have made use of chloride of barium, I conclude 

 that it has the effect of destroying any injurious 

 properties which may be in the paper, and more 

 especially with respect to the size ; and besides 

 which, when combined with iodide of silver, 

 greater intensity is obtained in the negative. 



I have occasionally prepared paper without 

 chloride of barium, but I have always found (ex- 

 cept for positives) that I could not rely upon it 

 with the same degree of certainty. I need scarcely 

 add that throughout the whole of this process the 

 greatest care and attention is required, and that 

 the water should be constantly agitated while the 

 paper is in it, and that the water should be once 

 changed. W. J. Newton. 



6. Argyle Street. 



Lady NevelVs Mnsic-book (Vol. vii., p. 59.). -* 

 To transpose the six-line staves of old music into 

 the five-line staves of modern notation, it is only 

 necessary to treat the lowest line of the treble, 

 and the highest line of the bass, as ledger lines. 

 The five remaining will correspond with the five 

 now in use. 



I should feel greatly obliged to your corre- 

 spondent L. B. L. for a sight of this Virginal Book, 

 as it appears to be an exact transcript of the one 

 in Dr. Rimbault's possession. Wm. Chappell. 



201. Regent Street. 



Tuch (Vol. vii., p. 82.). — Alphage suggests 

 that the "touchstone" had its name because "a 

 musical sound may be produced by touching it 



