562 



NOTES AND QUERIES. 



[No. 163. 



"We all know that, after spoiling a dozen or 

 twenty pictures, which have perhaps cost us much 

 toil and fatigue to procure, and which, in many 

 cases, we cannot ti'y for again, we sliall find out 

 how strong the solutions ought to have been, 

 Mr. Ckookes knowing all the time the exact 

 strength required. 



It is greatly to be desired that you would favour 

 us at once with Da. Diamond's paper processes. 

 The present state of the weather, so far from 

 affording a good reason for the delay, is, on the 

 contrary, just that which enables one to get all 

 things ready against the first outbreak of sunshine. 



There is a grievous inconvenience in the waxed- 

 paper process, as hitherto described, — I mean in 

 the development hy floating on the gallo-nitrate. 

 Of course, you can float only one sheet at a time in 

 the same dish ; so that a man bringing home 

 twenty views, each requiring to be floated an hour, 

 must either have twenty dishes at work, or con- 

 sume twenty hours in the development. I pre- 

 sume that immersion one upon the other would 

 not do. So also the paper has to be excited by a 

 careful floating on the aceto-nitrate for above ten 

 minutes, and then again washed hy floating on dis- 

 tilled water. I hope Dr. Diamond will have been 

 enabled to simplify this process. 



Very unkind of Da. D.'s friend not to have told 

 him what proportions of amber to use in his col- 

 lodion : for I consider this a valuable hint. 



Da. Diamond, p, 320., recommends "amber" 

 for one varnish, and a few lines further on "the 

 common amber of commerce " for another varnish. 

 What is the difference, and where are they to be 

 procured ? I. W. 



[No amber is better than the broken mouth-pieces 

 of pipe stems and cigar tubes, being entirely free from 

 extraneous substances. They may be bought for about 

 2s. per oz. of many tobacconists, and especially of On- 

 derwich, the German pipe merchant, Princes Street, 

 Leicester Square. The common amber of commerce 

 may be procured at the varnish -maker's oc chemist's, 

 and although it gives a varnish it is always coloured, 

 and not so satisfactory as the finer sort.] 



Solution for Positive Paper. — Probably some 

 of your correspondents will be good enough to 

 say, what the strength of the solution for positive 

 paper should be, when chloride of sodium (common 

 salt) is used for the preparatory processes instead 

 of muriate of ammonia; and what strength of so- 

 lution of nitrate of silver to be applied with a 

 brush should be used afterwards to render the 

 paper sensitive? 



I have followed Le Gray's directions, in using 

 one part saturated solution of common salt, and 

 three parts water ; and for the nitrate of silver 

 ninety-six grains to the ounce of distilled water ; 

 but I find that it is requisite to apply three 

 washes of the nit. sil. solution before the paper is 



rendered properly and easily sensitive, and this 

 of course is troublesome. After the first wash, 

 the paper on exposure will only become of a faint 

 slate colour ; after the second it deepens irregu- 

 larly in blotches, and cloudy; but after the third it 

 darkens quickly and uniformly on exposure, even 

 on a day that is not very bright, at this season of 

 the year. 



'I'he paper I have used is Nash's. I prefer the 

 tone of colour obtained for the positive by using 

 chlor. sodium to that given by mur. amm., at 

 least for portraits. By using mur. amm. I have 

 found a single wash of nit. sil. solution sufficient, 

 but that the paper requires a much longer expo- 

 sure to deepen sufficiently, than that prepared 

 with chlor. sod. and three washes of nit. sil., as 

 described. C. E. F. 



Photography applied to the Microscope, Sec. — 

 One of the earliest uses I made of collodion was to 

 apply it to taking the images through the micro- 

 scope : in fact, I may say that on the first day 

 that Mr. Archer introduced to me the collodion, 

 in the autumn of 1850, some experiments were 

 performed, and the images of monochromatous 

 substances, as sections of wood, fossil infusoria, 

 &c., seemed to be very successful ; but in animal 

 tissues, where a great deal of yellow or yellowish- 

 brown prevails, the productions appear to be 

 very inferior from drawings made by the camera 

 lucida. Some of my friends carried these experi- 

 ments to a great extent, and multiplied their 

 results by printing from the negatives. I would 

 beg to mention also, that the film of collodion has 

 been successfully floated off the glass, and taken 

 up upon prepared copperplates and wood, upon 

 both of which etchings and wood engravings have 

 been made, — the operator following nature's lines 

 in his delineations, instead of relying upon his own 

 imperfect powers of drawing. H. W. D. 



Origin of Collodion : French and English 

 Weights and Measures. — In your No. for Oct. 30. 

 there is an inquiry by Q. Q. as to the origin of 

 the name of collodion, and who first recommended 

 its use in photography. I cannot tell him who 

 gave it the name of collodion, or the origin of the 

 name; but it was discovered by Le Gray in 1849. 

 He mentions it in his work on photogrnphy ; and 

 the whole of the process, &c. The work may be 

 got at Claudet's or Henneman's, of Regent Street. 

 The work is in the French language. I have 

 but just become a subscriber to " N. & Q. ;" I 

 should therefore feel obliged if you, or some of 

 your subscribers, would inform me in which of the 

 back Numbers I may find an account of the French 

 weights and measures; their relative value com- 

 pared with the English, &c. G. C. 



[In Brande's Chemistry, the relative value of the 

 French and English weights and measures is fully ex- 

 plained, as well as in many elementary works.] 



