130 



NOTES AND QUERIES. 



[No. 277. 



losopber of Upsala," and bis favoured rival, a 

 certain (einem gewissen) Herr Wallmark, whose 

 Journal for Literaturen och Theatern issued an- 

 tiquated and empty criticism from 1809 to 1814. 



I have found no other notice of Hoijer, and the 

 only work of his which I know is entitled Af hand- 

 lung om den Philosophiska Constructionen, af Benj. 

 Carl H. Hoijer, Stockholm, 1799, pp. 202." The 

 original of the passage quoted by J. A.^E. is at 

 p. 119. : 



" Forklarar den ei hoad den skall fdrklara ; den for- 

 klarar genom en cirkel. Tingen och realitaten skola fdr- 

 klara tingen och realitaten. Det absoluta tinget ar en 

 drom ; men den i allmanna lefvernet utom den toma spe- 

 culationen gallande realitaten ar och blir den enda ver- 

 kliga, och borrtages den, sa forsvinner afven dess forkla- 

 ringsgrund." 



A better translation might be given, but my 

 knowledge of Swedish is very superficial ; and to 

 translate metaphysics, one ought not only to know 

 a language well, but to be familiar with its onto- 

 logical phraseology. 



J. A. E. asks, " Was Hoijer a follower of 

 Fichte ? " I think not ; for, though giving Fichte 

 high praise for acuteness, and assenting to many 

 of his doctrines, he differs often and too freely to 

 be held a follower. I give this opinion with some 

 diffidence, warned by the example of Fortlage, 

 who is reproached by Frauenstadt (Briefe ilber 

 die Schopenhauer" sche Philosophie, p. 45.) with 

 classing Schopenhauer among Beneke and the 

 realists. When two such men differ as to the 

 meaning of a third, writing in their own language 

 on matters with which they are thoroughly .con- 

 versant, a foreigner may well be cautious. 



H. B. C. 



U.U.Club. 



PHOTOGRAPHIC CORRESPONDENCE. 



Bromo-iodide of Silver. — Your correspondent Bromo- 

 lODiDE, who commenced this chemical debate last No- 

 vember, will be gratified to find that Mr. Lyte and Mu. 

 Leachman admit his real existence, and that the only 

 practical question is how to throw him down. Mr. 

 Leachman confirms my statement that the whole of the 

 silver in a solution of the double bromide and double 

 iodide of silver, is precipitated by water. Hence it is only 

 necessary to prove that in mixing these solutions the 

 bromide of silver is not converted into iodide. Now it is 

 ascertained by experiment that equal quantities of bro- 

 mide and of iodide of silver require the same quantity of 

 iodide of potassium to effect their perfect solution. Thus, 

 80 grains of each of the former are dissolved in 650 grains 

 of the latter, and a less quantity is insuflicient. But if 

 80 grains of the bromide are to be converted into the 

 iodide, it would require 74 grains of iodide of potassium to 

 supply the requisite quantity of iodine ; and a perfect so- 

 lution of the precipitate could not be effected without 724 

 grains of iodide of potassium, which is contrary to ex- 

 periment. Moreover, the conversion would be farther 

 proved by the change of the peculiar whiteness of the 

 bromide into the characteristic yellow tint of the iodide, 

 which again is contrarv to exneriment. The case of the 



double bromide and double iodide is still stronger. For 

 here, if the former robbed the latter of 74 grains of iodide 

 of potassium, a large precipitate of iodide of silver would 

 be immediately formed on mixing these solutions. Ex- 

 periment, therefore, appears to confirm both my theory 

 and my facts, and practical men may attack red and 

 green as readily as blue and white. 



Mr. Leachman is also in error in supposing that I 

 compare Dr. Diamond's solution with "ordinary calotype 

 paper." He will find, on reference to my note in Vol. x., 

 p. 472., that I compared it rigidly with " Mr. Talbot's 

 calotype paper." The former, as he is well aware, is well 

 washed for at least four hours in many changes of water ; 

 the latter, after remaining for one or two minutes in a 

 solution of iodide of potassium, is mereh' dipped into 

 water, and consequently is very far from being free from 

 that compound, which greatly impairs its sensibility. In 

 fact, there is as much difference between the well- washed 

 paper and the dip, as there is between a pint of brandy 

 pure and a pint of brandy mixed with a quart of water. 

 I admit that Dr. Diamond's paper is not superior to 

 "ordinary calotype paper" in sensitiveness, but only and 

 especially in its action on those tints upon which pure 

 iodide of silver can make no impression. J. B. Reade. 



I have been very much pleased with reading the dis- 

 cussion which has taken place in " N. & Q." relative to 

 my recommendation of bromo-iodide of silver for negative 

 calotype pictures ; and 1 trust even to your non-photo- 

 graphic readers that this friendly controversy has not 

 been useless. It may induce some to undertake photo- 

 graphic views when they learn that the greens of a land- 

 scape may be much more perfectly delineated than 

 formerly ; for no doubt the indistinctness of delineation in 

 this respect has caused an indiflference in many to attempt 

 photographic productions. I will not say one word in 

 addition to what I conceive Mr. Reade has so ably urged, 

 beyond bearing witness to the accuracy of the experi- 

 ments which have been conducted in elucidation of the 

 question ; but I appeal to the practical results. If I find 

 the inclosed landscape has all the detail in foliage which 

 an artist would bestow or desire, and that this result is 

 obtained on paper prepared as I have suggested with 

 bromine as well as iodine, and if I find contrary results 

 when iodine alone is used, I think the argument of ima- 

 ginary decomposition having taken place to be perfectly 

 set aside. 



Again, will you cast your ej'e on the inclosed portraits 

 of a well-known antiquary, taken in a few seconds on a 

 dull December day; in one, the scarlet coat and dark 

 trowsers, and in the other the tabai-d, ivith all its various 

 colours, arc delineated with all the proper gradation of 

 tone. The collar of SS even is not solarised, another 

 benefit I attribute to bromine being the mitigation of the 

 over-exposure, of the high lights. It may not be inap- 

 propriate here to make a reference as to the difference 

 between actual practice, and mere scientific theory with- 

 out it ; for it has been observed by some that a fractional 

 part of a drop of nitric acid added to the nitrate of silver 

 bath, completely destroys its power of producing rapidly 

 good pictures; whereas the bath used on this occasion 

 was made with a sample of nitrate of silver so strong of 

 nitric acid that the cork and leather with which it was 

 secured in the bottle were destroyed by the fumes of the 

 free acid. Hugh W. Diamond. 



[We have of course seen the photographs alluded to by 

 Dr. Diamond, and can bear testimony to the accuracy 

 with which that gentleman describes the peculiar cha- 

 racteristics which thev exhibit. — Ed. "N. & Q."l 



