204 



NA TURE 



[June 30, 1898 



I once speared in that way fifty fishes weighing 300 

 pounds altogether, which were following a log on the 

 Atlantic ; and their number seemed not to have been 

 much lessened by such a breach. Another day, while 

 I was alongside a log, very anxious to make a good bag, 

 because I had just picked up the crew of an English 

 vessel, the Blue attd Whitt\ sunk under my eyes, and we 

 were already short of provisions, I was disturbed in 

 this occupation by a large shark, who was himself living 

 about the log, and who, after having looked at me with 

 his cruel eyes, stuck himself under my dinghy. His 

 head and his tail projected beyond the ends of this boat, 

 and the friction of his back against the keel gave a 

 rather uncomfortable feeling. Therefore, after I had 

 made a few catches of the usual fishes, which gave 

 him some excitement, I left the log and returned on 

 board, escorted for some distance by the disagreeable 

 wanderer. 



On the other hand, we have on many occasions caught 

 dozens of tunny fishes in a day by simply using the 

 aforesaid tow-line. 



Thus I can state that many sailors wrecked on the 

 Atlantic, and abandoned for days and weeks on its 

 apparently uninhabited wilderness, have died of hunger 

 among a most abundant and attainable food, and that 

 they could have been saved had they simply known it, 

 and possessed the very simple gear required. Therefore 

 I think that all the principal boats of a ship ought to be 

 permanently provided with a few lines and hooks and 

 with a fish spear. 



There is no very obvious explanation of the fascination 

 which any floating or drifting object seems to have for 

 marine animals of various sorts. Even turtles, which are 

 very stupid, and sperm whales or other cetaceans, which 

 seem intelligent, are attracted by a buoy or by a ship, and 

 any kind of apparatus brought up from the depth, even 

 a cable end, is often accompanied by single fish or small 

 companies, which get hopelessly bewildered when the 

 object disappears out of the water. 



REPRODUCTION BY PHOTOGRAPHIC 

 PROCESSES. 



T T is not difficult to understand the survival and general 

 ■»■ adoption of those photographic methods in which the 

 light, by shining upon the sensitive surface, produces 

 shading or blackness. Although the first product, as 

 obtained in the camera, by such a process is itself useless 

 as a photograph, the lights and shades being reversed ; 

 this " negative," as it is termed, becomes a means of repro- 

 duction, as by laying the negative over a sensitive surface 

 rnore or less similar to that first used, and allowing the 

 light to shine through it, any required number of prints 

 or copies in true light and shade may be obtained. Such a 

 process is necessarily slow, as in working upon this system 

 the production of each individual print or photograph 

 involves an exposure to light, and the rapidity of repro- 

 duction is limited by the chemical intensity of that light 

 which is available, and also by the sensitiveness of the 

 material used. 



Another system of reproduction, and one which is 

 month by month becoming of greater industrial im- 

 portance, evades the necessity of a special exposure to 

 light for obtaining each individual print or copy, this 

 being effected by the production of a printing surface or 

 plate from which copies may be printed by mechanical 

 means. Prints obtained by a special exposure to light 

 for each copy are often called solar prints, or true photo- 

 graphs, while those prints which are printed mechanically 

 from a plate or surface which itself is photographically 

 produced, are now so generally called process prints, that 

 NO. 1496, VOL. 58] 



the title of "The Process Year-Book" ^ is by no means 

 ambiguous in its meanmg to those who are current with 

 the technological phraseology of the day. " The Process 

 Year-Book" well represents the present state of process 

 craft, not only by giving numerous representative illus- 

 trations, but by articles from the leading authorities in 

 such matters. The articles are, however — as should be in 

 a work of this kind — written rather for the expert than 

 for the comparative outsider, and we shall give our readers 

 a better general idea of the development and present 

 condition of reproduction by the photo-mechanical pro- 

 cesses if we drift away from our text, than if we confine 

 our remarks to the matter before us in Mr. Gamble's 

 volume. 



It is interesting to note that the early experiments of 

 Nic^phore Niepce, which were commenced as far back as 

 18 13, were undertaken with the view of obtaining printing 

 surfaces by photographic agency, so the history of photo- 

 graphic process work includes the first chapter in photo- 

 graphic history. Niepce coated lithographic stones or metal 

 plates with a varnish the solid material of which tends to 

 become insoluble in its menstruum where exposed to light. 

 There are many such varnishes, and as an example we 

 may mention a solution of bitumen in a volatile oil like 

 that of turpentine. Those portions of the film which are 

 still soluble after exposure are next dissolved away, while 

 the insoluble portions form a ground, or resist against the 

 etching fluid, which is next used. Aheliographic etching 

 on metal by Niepce, made about 1824, is still extant, and 

 in 1827 he brought several specimens to England ; but 

 very little attention was given to photographic matters 

 until, in 1839, the daguerreotype was introduced with its 

 perfect rendering of the most delicate degrees of light 

 and shade, and this by a very short exposure in the 

 camera. 



Considering that the daguerreotype image is of the 

 nature of a deposit on a smooth metal surface, the idea of 

 moulding by the electrotype process so as to produce an 

 intaglio printing plate, naturally presented itself ; as also 

 that of etching the metal, in the hope that the image on 

 the surface might serve as a local resist. Grove, Chevalier, 

 Claudet and others made experiments with the view of 

 obtaining printing plates from the daguerreotype by such 

 methods, but most etchings were wholly unsatisfactory ; 

 and although the electrotype casts of the plate were per- 

 fect as reproducing in intaglio every tone of the original, 

 the plate had neither that grain nor that depth which are 

 essential to the satisfactory printing of a photo-engraved 

 plate. 



Mr. Fox Talbot, whose Calotype or Talbotype process 

 on paper was made public practically at the same time as 

 the daguerreotype, was one of the first to produce satis- 

 factory intaglio printing plates, and his method is 

 specially interesting as being the basis of that process of 

 intaglio photogravure which is most in use at the present 

 time. Talbot coated the metal plate with a wash or film of 

 gelatine made sensitive to light by the addition of bichro- 

 mate of potassium, and he exposed under a transparent 

 positive. Where the light acted to the full, the gelatine 

 became impervious to aqueous fluids ; but where protected 

 from the light, the film allowed such fluids to pass readily, 

 and between these extremes were all degrees of inter- 

 mediate resistance to the passage of the aqueous etching 

 fluid. Talbot used such saline etching materials as plat- 

 inic chloride or ferric chloride, and from time to time he 

 suggested and used various methods of producing an ink- 

 holding grain, such as a resinous dust, a network, or a kind 

 of aqua-tint ground formed by the evaporation of a 

 solution of camphor and common resin in chloroform. 

 The chief present-day method of photogravure is Herr 

 Klic's modification of the Talbot method, the chief differ- 



1 "The Process Year-Book, a Review of the Graphic Arts." Conducted 

 by William Gamble. (London and Paris : Penrose and Co.) 



