I could send you a Note on a cognate subject, but I fear it would occupy too much of your space,—that of Happy Isles, or Islands of the Blessed. The tradition respecting these happy isles is very wide-spread, and obtains amongst nearly every nation of the globe; it is, perhaps, a relic of a primeval tradition of Eden. Some have caught glimpses of these isles, and some more favoured mortals have even landed, and returned again with senses dazzled at the ravishing sights they have seen. But in every case after these rare favours, these mystic lands have remained invisible as before, and the way to them has been sought for in vain. Such are the tales told with reverent earnestness, and listened to with breathless interest, not only by the Egyptians, Greeks, and Romans of old, but by the Irishman, the Welshman, the Hindoo, and the Red Indian of to-day.
Eirionnach.
[ PHOTOGRAPHIC NOTES AND QUERIES.]
Photographic Collodion (Vol. vii., p. 314.).—In a former communication I pointed out the wide differences in the various manipulations prescribed for making the photographic gun cotton by several photographers: differences most perplexing to persons of small leisure, and who are likely to lose half the opportunities of a photographic season, whilst puzzling over these diversities of proceeding. Suffer me now to entreat some one to whom all may look up (perhaps your kind and experienced correspondent Dr. Diamond will do this service, so valuable to young photographers) to clear up the differences I will now "make a note of," viz. as to the amount of dry photographic gun cotton to be used in forming the prepared collodion.
On comparing various authors, and reducing their directions to a standard of one ounce of ether, I find the following differences: viz., Dr. Diamond (Vol. vi., p. 277.) prescribes about three grains of gun cotton; Mr. Hennah (Directions, &c., p. 5.) about seven grains; the Count de Montizon (Journ. of Phot. Soc., p. 23.) eight grains; whilst Mr. Bingham (Supplement to Phot. Manip., p. 2.) directs about thirty-four grains! in each case to a single ounce of ether.
These differences are too wide to come within even Mr. Archer's "long range," that "the proportions ... must depend entirely upon the strength and the thickness required ... the skill of the operator and the season of the year." (Archer's Manual, p. 17.)
Cokely.
Filtering Collodion.—Count de Montizon, in his valuable paper on the collodion process, published in the second number of the Journal of the Photographic Society, objects to filtration on the ground that the silver solution is often injured by impurities contained in the paper. It may be worth while to state, that lime, and other impurities, may be removed by soaking the filter for a day or two, before it is used, in water acidulated with nitric acid; after which it should be washed with hot water and dried.
T. D. Eaton.