Photography and Science.

New Zealand Graphic, Volume XL, Issue 6, 8 February 1908, Page 39

Photography and Science.

FLOWER PHOTOGRAPHY. Lecturing to the South Suburban Photographic Society upon flower photography, Mr. E. Seymour said that he woratnl in a corner of an old coachhouse, about three feet from a window which was covered with cheap art muslin to soften the light. Till quite recently he had used only a commonplace field camera with a cheap French lens. His bench was an old packing case, covered with a piece of brown paper that once served as wrapping for * parcel. Sometimes the form of the spray suited the composition as it grew; but generally he had to snip pieces off, and to build up the arrangement with pins of various sizes, tin tacks, florists’ wire, and seccotine, so as to get precisely what he wanted. For big subjects which were likely to cast heavy shadows he used a dark background ; where the shadow cast was light he used a lighter background. He did not employ an orthochromatic screen, though he used Barnet ortho plates. But then he seldom photographed anything blue. As far as possible he stuck to the yellows, and avoided mixing his colours. He thus avoided excessive contrasts. He always over-exposed, and developed with a pyro-sdda developer, strong in pyro. But he never developed fully, never developed for pluck. He took his plate out of . the developer as soon as the highest’ light showed detail; and before it clogged up. Some people would call his negatives mere ghosts when they came out of the hypo. Asa rule he intensified them with mercuric iodide, and thus got the pluck which others got by development—only he' kept the detail in his high lights. til With shallow flowers he always used side lighting, but when they were of the deeper sort, such as lilies, he turned them ,three-quarter face to the window. His greatest trouble was movement. During the long exposures he had to give the flowers sometimes curled and contracted so as to spoil the negative. Strange to Bay, the freshest flowers were not always |(if ever) the best for his purpose. Some of his finest effects were obtained from withered specimens. Fresh or withered, however, he - always “varnished” his leaves before he exposed on them. The varnish was cold water laid on lightly with a sponge. ORIGIN OF PRECIOUS ORES. ... Men sometimes dream of enormous wealth stored deep in the earth, below the reach of miners; but according to an eminent geologist there is little or no ground to believe that valuable metallic deposits lit very deep in the earth’s crust. Such deposits, according to this authority, are made by underground waters, and, owing to the pressure on the rocks at great depths, the wates are confined to a shell near the surface. With few exceptions, ore deposits become too lean to repay working below three thousand feet. Nine miners in ten, taking the world as a "whole, are’" poorer ’ in the second thousand feet than in the first thousand, and poorer yet in the third thousand than in the second. ♦ ♦ ♦ MANUFACTURE . OF GUT STRINGS. Catgut strings, it is well known, are made of the intestines. of sheep. The intestines of the full-grown animal ara from forty-to fifty feet long. i; The raw material from the stockyards is first thoroughly cleansed of fat and fleshy fibre by dull knives arranged on a drum turned by a crank. The white tough membrane that is left is then handed over to the splitter, who dexterously splits the material into even strands by bringing it against the blade ®f a safety razor set upright in the tab-

Je before him. The strands are then spun together and placed on the drying frames. An American E violin string requires six strands; the European, four. The strands, at one end fastened to an upright post, are twisted together, while still damp and pliable, by means of a spinning wheel. Taken from the drying frames, the strings are cut in lengths, coiled, and boxed in oiled paper for shipment. To polish the strings, very fine emery paper, laid on a grooved aluminium block, is used. While the strings are still on the drying frame, the covered block is passed over the strings, polishing as many at one time as there are grooves in the block. It can be seen that from the manner in which the strands are twisted the effect of polishing is to weaken the string. In the essential features, the process of making the fine gut strings for surgical uses, or the heavy strings threeenghths of an inch thick sometimes employed for machinery belting, does not differ from the method employed in the case of the musical strings, except that the latter are handled with more care.

THE ULTRA MICROSCOPE. The ultra microscope is a recent device of science. By its aid it is expected that many micro-organisms which have hitherto defied observation will be detected. As the classification of microbes has advanced, biologists have inclined to the conclusion that many must still remain unknown, too small to be perceived with any instrument hitherto in use. The new apparatus is the invention of two Frenchmen, Cotton and Monton. It involves no change in the existing arrangement of lenses. It is the system of lighing that is revolutionised. The ray is used at right angles to the axis of the instrument, instead of coinciding with it. Thus the light sweeps across the objective parallel with its plane. By this means it is said that many particles so small that they have defied detection under the most powerful glasses become visible as brilliant points. It is a new world, enthusiastic microscopists say, that is opened to scientific study. ♦ ♦ ♦ SHAWL MAKING IN INDIA. The manufacture of Kashmir shawls, which fifty years ago afforded occupation for whole villages and thousands of families in the province of Kashmir, is an almost extinct industry. Formerly the possession of a pair of the genuine Kashmir shawls was the hall mark of nobility, or at least of high social status, among Indian families.

To-day, we are told, the cheap imitations manufactured in the Punjab, and the machine made article from Europe dyed with aniline in striking hues and patterns, are supplanting the hand made shawl of native workmanship. An occasional order for a couple of shawls at a moderate price, to satisfy the passing whim of a potentate, or the fact that the Maharaja of Kashmir has a few shawl tents which require repair and renewal. docs not suffice to keep alive the workman or the industry. The manufacture of the real Kashmir shawl is almost wholly a manual process. The material is the soft wool of the Tibetan goat. Hand spindles are used in the preliminary operation of converting the wool into yarn; the weaving of the yarn into a texture of inimitable fineness is done entirely by hand looms manipulated with the utmost dexterity; ami the coloured woollen border is then interwoven. The dyes are natural and indelible. It is believed that the water of certain lakes ami streams, in which the shawls are dipped, has virtue to make the colours permanent.