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simple, within the capabilities of any intelligent man to construct for his own use. The materials are readily obtainable, for zinc can be bought everywhere, and boxes made of it can be had of any tradesman handling that metal, from whom also can be had the inner iron stove. The air-cell lagging is made use of by plumbers, builders, setters of steam engines and furnaces, and can be procured at the business houses supplying materials to these tradesmen. The filling in with lagging or mineral wool necessitates that the outer box (see Fig. 2) shall be lined with metal, but this can be obviated if other asbestos products are used. The asbestos may be of "roll fire-felt" or "sheet fire-felt," manufactured by the H. W. Johns Company. The " roll " is 36 inches wide, from ,"5 to % of an inch thick, and sells at 6 to 10 cents per square foot, according to thickness. The "sheet" is 3 x 2 feet, from ^ to 2 inches thick, and sells at 15 to 35 cents per square foot. The "sheet " is quite light in weight, and seems to be well adapted to the purpose. Or an asbestos cement could be laid on the oven, of any desired degree of thickness. The H. W. Johns Company makes an " asbestos plastic stove lining " for stoves, ranges, furnaces, which is easily laid on with a trowel, will not warp, is fireproof, costs for 5-pound cans, 50 cents; for 10-pound cans, 75 cents, and for pails of 25 and 50 pounds, 5 cents per pound; also " asbestos retort cement," which adheres readily to stone, wood, or metal, is fireproof, can be applied with a trowel, hardens rapidly, vitrifies without shrinking, is not injured by nitric or sulphuric acids, petroleum oils, etc., costs 60 cents for 5-pound cans; $1 for 10-pound cans, and at 6 cents per pound for 25 and 50-pound pails. This also could be employed to coat etching tubs, etc. The same firm also manufactures " asbestos mill-board," acid and fireproof, in sheets 40 x 40 and 42 x 44 inches, from J'j to ^ inch thick, the 40 x 40 sheets weighing (according to thickness) from 2 to 25 pounds each, and costing 10 cents per pound. It will be required to use this or the "sheet fire-felt" if the outer oven is simply a frame. The " mill-board" is heavier than the " sheet fire-felt"—the latter we consider the best material for the purpose. Of course, the thickness of the asbestos depends upon the size of the oven, but for an oven the size of the Aladdin about inch would be sufficient. If when heating a zinc or copper plate, after dusting with resin powder or coating with enamel, a piece of this mill-board, or of "asbestos paper," or even one of the "asbestos stove mats," sold at household furnishing stores, is placed on the stove, or under the plate, it will be found that the heat is radiated capitally, and the metal is more evenly heated. Any of these materials can be placed under the can when boiling emulsions or dissolving glues, and it will act in the same manner, maintaining a steady heat and preventing burning. The asbestos paper is sold in packages of one dozen sheets, 9 x 14, at 10 cents per package, and the stove mats cost 5 or 10 cents each. Indeed, it would be a good plan to coat the outside of the boiling can with asbestos cement, to assist in maintaining a steady heat when in the water bath.
Both asbestos cloth and asbestos fiber are used for filtering chemical solutions, and arc purified by putting in the fire. The cloth is made into towels for washing and wiping vessels. It can be folded up to protect the hands when taking off anything hot. though it will not be required when grasping a glass of "hot Scotch." The cloth is of three thicknesses, from 25 to 36 inches wide, and costs from Si.90 to 83.50 per yard. Asbestos mittens and gloves are also procurable; they range in price from §2.20 to $2.85 per pair. We have specified only a few of the uses to which asbestos may be put.
A lady once said in our hearing that, "A man was always thinking of something good to eat," and, assuming she was correct in her remark, we will return to Mr. Atkinson's cooking oven, which has now been tested for a number of years, and is highly praised by those persons who have it. By his method of cooking, the food is much more nutritious and palatable than when done by the ordinary stove, and is much more economical, as what are considered undesirable cuts of meats can be made into tasty dishes. The process man, who has one of the Aladdin ovens, could, after cooking his plates, turn it over to the " Missus," who then could cook the dinner, and then, as the oven almost takes care of itself, what a boon it is to the bachelor. All the poor, lone man has to do at night is to put his breakfast into the oven, light the lamp, say his prayers, and get under the covers of his bed, conscious that when he arises in the morning he will have his meal ready and nicely cooked, and he can fix up his dinner before going down town to business, let the oven do its part, and, on returning home, sit down to a satisfactory repast. A Boston newspaper man carried out this plan, and has published his " experiences." The United States Department of Agriculture at Washington has published two pamphlets— "Suggestions Regarding the Cooking of Food," by Edward Atkinson, and " Suggestions for the Establishment of Food Laboratories," Office of Experiment Stations, Bulletin No. 17—which describes Mr. Atkinson's invention. These pamphlets can be obtained gratis from the Department.
H. T. Dlfeield.
The Camera Club, New York.
PEN DRAWING FOR LINE BLOCKS.
Benedict & Company, engravers, Chicago, give this advice: A smooth, white surface is a first requisite. Fair drawings may be made on the best quality of unruled writing paper, but good Bristol board is better. For some drawings the " double enameled board" is excellent, as the blacks may be laid on full with a brush, and the white lines produced afterward by scratching through the ink and enamel with a steel point. Whatman's drawing paper, or any paper with a rough surface, is unfit for the purpose. Use an india-ink that will produce a perfectly black line, or photo-drawing ink. If the lines are pale, brown, gray, or broken, they will come out feeble and imperfect in the plate. All lines, therefore, the finest as well as the coarsest, should be perfectly black. Grades of color must be produced, not by varying degrees of paleness, but by the size and space between the lines. Use a pen that will give a fine, even line. Steel pens are best. Gillott's Nos. 170 and 290 are excellent. For a fine quality of engraving make the drawings twice the length and width of the plate desired. Reckon seventy to one hundred lines to the inch as the fineness of the plate, and make accordingly one-half as many in the drawing. But take care that the lines are not so fine nor so close as to make a plate that will fill up in printing. Always make sets of drawings for the same reduction, as it obviates the necessity of making separate negatives. Very good work can be done from drawings made one-half or one-third larger than the required plate. Drawings should not be made in reverse. Make the pencil lines with blue pencil, as blue will not photograph. Never cross-hatch till the first set of lines is perfectly dry. Erase all pencil marks, taking care not to remove any of the ink. Keep a blotting pad under the hand, but do not use it to take up ink from the drawing. Leave a margin of half an inch around each drawing, for tacking on the camera board. White lines may easily be drawn over black ones. Apply best Chinese white with a quick stroke from a full pen or brush. Mix it thick, and do not go over a line the second time until the first is quite dry.
Fleck writes that, so far as he is aware, there has hitherto been no practical use of steel for photogravure. He says that it is, indeed, an open question whether it has yet been tried, and yet it is simple, easy and practical. A photogravure etched in copper must be cleaned off and hardened, after an edition of some one thousand copies has been printed from it. If the etching is made directly on steel, labor and loss of time during cleaning and hardening would be saved, and sharp prints would be obtained throughout the whole edition. Fleck claims also that the process is easier, the progress of the etching being more easily watched than when copper is employed. Chloride of iron also etches steel better than it does copper and is the best etching medium, bearing the same relation to steel as nitric acid to zinc.
At a recent lecture on the preparation of plates for collotype printing, Mr. Wilkinson emphasized the necessity of avoiding damp and of maintaining throughout an uniform temperature. Very thick plate glass is carefully ground upon one side by rubbing with fine flour emery for some minutes. It is then coated with a substratum consisting of 4 ounces each four-ale and porter, 4 to 12 drops of ammonia, .880, to which is added 1 ounce of silicate of soda just before using. After drying, the plates are rinsed under the tap for a few moments, and again dried, when they can be kept indefinitely. For the sensitizing process an oven will be required, and kept at a temperature of not more than 120 degrees. A stock solution is made of: Methylated spirits, 1 pint; tincture of tolu, 1 ounce; chromic acid, 5 grains; and the sensitizing mixture consists of collotype gelatine (Swiss), 150 grains; water, 2 ounces; potassium bichromate, 37 grains; above stock solution, 1 ounce. The spirits must be added gradually, and the solution well stirred. Of this solution 4 to 5 minims will be required per square inch of plate for coating. The plate is then placed in an oven and "cooked" for forty-five minutes. A reversed negative is required for printing, the margin of which must be "blocked out" with tinfoil. The prepared plates should be kept from one to fourteen days face to face before printing. Mr. Wilkinson recommends an open-back printing frame, in which an average exposure of thirty minutes to good (but not sun) light, or several hours in dull weather, will be necessary. After exposure the plate must be washed for a few hours to remove the free bichromate. ^ ^
Preparation Of Lithographic Stones For Fine Engravings.— The following method is given by The Paper Digest, translated from a German contemporary:
"Dilute liquid gum arabic in oxalic acid, and rub it with a flannel rag on the surface of the stone until thoroughly dry. It is generally known that by this process the polish of the surface is materially enhanced. But it is a question whether the use of the acid is not prejudicial to the excellence of engravings which are intended for conservation during many years.
"The following polishing process is, therefore, recommended: After the stone has been cleanly polished, it is coated over with a caustic solution of gum, which, after drying, is carefully washed off. The stone is then rubbed off with so-called lead paper, some fine emery, and water for a few minutes, whereby the excess of roughness is removed from the surface. After this is washed off again, the surface is polished with a ball and a small knife point of tin ash and brimstone and some water, whereby in a few minutes it will secure the most perfect gloss. The stone is washed off, and can be stored away until needed for use.
"Stones polished in that manner, on account of their great smoothness, retain just as little color as copper plates, and the gummy preparation keeps them clean as well as oxalic acid would do, without possessing the latter's detrimental properties."
The Artist is quoted as saying that process would touch perfection by 1900 A. D., provided it continues improving at like pace with what it has recently accomplished. Then, and not till then, will comparison between its possibilities and those of wood engraving be adequate. Wood engraving is a perfected art, and the Artist's idea that process must have reached its highest point of excellence before a just idea can be had by comparing the two is a good one. Unfortunately, the arts (says Paper and Press), like everything else, are subject to reverses, and the infusion of commercialism into process work will sadly militate against anything like perfection unless the point of view of its votaries is radically changed. Process work must be regarded as an artistic avocation before the best that is in it can be brought out. Nowadays, it is in danger of becoming a manufacturing industry.
A Very valuable, in fact, a necessary, addition to darkroom facilities when using process dry plates is a soft piece of chamois skin, or wash leather. This should be wetted and then wrung out as dry as possible. After the gelatine negative is fixed and washed, the chamois is formed into a pad and the face of the plate patted gently with it. This removes the excess of moisture from the gelatine. The back and edges of the plate are then wiped dry, when the negative is ready for its bath of alcohol before the final drying.
The following has been suggested as a clearing medium for process negatives instead of the iodine and cyanide commonly used:
Potassium ferricyanidc (10 percent, solution) 1 part,
Potassium cyanide (2$ per cent, solution) 50 parts.
If the whole of the negative is to be submitted to the action of the reducing solution, it is placed in a black dish, it being much easier to tell when the lines are clear if the negative is on a dark ground. The above solution is poured over the negative, and directly after the lines are cleared, the negative is quickly washed under the tap.
H. A. Hyatt sends us a copy of his new illustrated catalogue, No. 14. This is a particularly interesting list, is compiled with the utmost care, and is right up to date. We would advise those interested in the progress of our art to write for a copy.
Commenting on Edward P. Thompson's book on "Rontgen Rays," reviewed here a month or so ago, Lord Kelvin writes:
"I received it only a few days ago, but I have already looked nearly all through it, with great interest. I have seen enough to know that I shall find much most useful information in it which will be always readily available, because of the very excellent method and care with which you have given references to authors, dates and publications, and I am sure that all who arc interested in the subject will find your book exceedingly valuable.
"All your statements with reference to anything I have done on the subject are perfectly correct.
"I believe that hitherto nothing in the way of diffraction has been discovered for the Rontgen Rays,"
The Sanders Engraving Company send us a copy of their new specimen book, which shows that our St. Louis friends are well in the front on process matters. Those interested in fine half-tone work should apply for a copy of this specimen book.
From Percy Lund, Humphries & Co., Limited, we receive No. 11 of the The Popular Photographic Series, The Camera and the Pen, by T. C. Hepworth. This is a capital work on the combined use of pen and camera for the
production of blocks for illustration. Price, 25 cents.
The first number of The Engraver and Electrotypcr, published by William Hughes, Fisher Building, Chicago, is to hand. The contents are written in chatty style, and intended for the general trade. We presume that the paper will soon take on a more ambitious appearance, for it is published in a center of photo-engraving that is second to none.
The Magic Lantern Journal and Photographic Enlarg Almanac and Annual for 1896-97 has been accorded a hearty reception, and is a publication that all interested in lantern matters should possess. The Use of Saturators, The Lantern in Advertising, Hints to Beginners, and a whole host of articles by competent writers, make the book a notable one.
Our illustrations again demonstrate the superior qualities of the cross-line screens issued by our publishers. These screens are particularly suited to all classes of half-tone work, and beginners in process work can obtain trial sizes at a low cost, with which much experimental work may be conducted.
It is said that an American papermaking firm will establish a mill in England, the object being to supply English publishers with paper of quality similar to that used here for high-class work.
But a few copies of the ninth volume of " The International Annual " remain unsold, and those of our readers who desire a copy should make immediate application for one. This volume is a particularly interesting one, and contains many illustrations that can be studied with profit.