SCIENCE NOTES & NEWS.

Waipa Post, Volume VIII, Issue 347, 8 September 1914, Page 3

SCIENCE NOTES & NEWS.

-> :o: (THE LOBSTER AND THE BUT.TEB* FLY.

The lobster is a relative of the! hui* terfly. Tlie kinship is not merely that of two members of tlie animal kingdom’. The lobster and the butterfly are aotw ually in one and the same great grouj) of the kingdom, like the clam and, the snail or the whale and the giraffe, whose species of activity are so wide* ly separated. It is simply, as Darwin pointed out in the case of other creatures a great many years ago, that the lobster and its friends, tliO crab, the prawn, and the shrimp, chose one method of life, while the butterfly and its’ set chose another. So the first group developed characteristics suited to the conditions in which they lived, including as one of the most important, as its members do not move rapid J ly, a coat of armour to protect them from their innumerable enemies; while the butterflies and the great host of other winged insects shed every bit of superfluous weight, trusting to swiftness to carry them out of danger, and to protective coloring to conceal theml when flight is unavailing. 8

GOLD PEN-POINT MAKING.

Metallic iridium, used so extensively for the points of gold pens, is made from the powder, obtained in the wet way from platinum ores, by heating to a high heat in a sand crucible and then adding stick phosphorus. The iridium, which cannot be melted alone, is ’thus fused in the form of an iridium phosphide. To remove the phosphorus the phosphide is heated with lime and the iridium is left in the form of a hard, white mass. It is now, so hard that it cannot be filed or cut, and is broken up into small pieces for soldering to the points of gold pens. These small pieces are ground to the right size on a copper disc wheel with emery or carborundum. It is said that an ounce of iridium will.make from Sooo to 10,000 pen points. It has also been found that the iridium thus prepared is practically as hard as the ruby. No steel tools can make an impression upon it. At one time much less expensive than platinum, iridium now is worth more on account of the demand for hard platinum, in which the iridium is the hardening agent.

COLD LIGHT,

Professor Charles Dussaud, a French' savant, gave in London a demonstration of his important invention, light without heat. This cold light, as he calls it, is obtained electrically in the usual way, only by interrupting the electric charge, thus making the light’ a series of flashes and rests, the lamp is not allowed time enough to become hot. The flashing is no rapid that to the eye the light is continuous. An 8-candle power incandescent bulb, with these interruptions of current, stands four times the voltage, the professor explained, and so gives 25 times the light, but this explanation of the invention, though shown yesterday, is not yet ready commercially, though shortly the public may able to obtain the better lighting and the greater; saving in current which it will give. The possibilities of cold light may be estimated when it is understood that among them is the elimination of the danger of cinematograph fires.) For the present powerful arc light producing great heat and occasional accidents can be substituted a small lamp giving the same amount of light without heat, and it is claimed at onethirtieth the cost.

Cold light, again, will greatly lessen the heavy cost of lighthouse lanterns, because the glass can be brought quite close to the illuminant without risk of breaking. It will dispense with magnesium in flash-light photography, and reduce considerably the present cumbersome and costly apparatus used in naval and military signalling.

MOUNTING PHOTOGRAPHS,

Photographic prints curl when they are mounted because the moisture on the exposed surface of the print evaporates more rapidly than that on the back, and so causes a shrinkage.; That draws the mount out of shape, unless it is very heavy. There are various methods of overcoming the difficulty. You can soak the print in a twenty per cent, solution of cerine and water, and then attach it to the mount by a dab of paste at each corner, or you can use one of the dry* mounting methods. Coat the back ofi the print with white of egg, lay it on the mount, and iron it with a hot flatiron. Nothing short of a miracle will get the print off again, yet the pro-, cess will not curl the thinnest mount. You can also get good results by dissolving white shellac in alcohol, and then painting the back of the print with the solution. When the solution is dry iron the print on, as already, described. You can buy a tissuepaper made especially for mounting, or can prepare one that will do the work satisfactorily. Make the coating for the tissue as follows: —Gum sandarac, three parts; gum copal, one part; shellac, one part; resin, one party alcohol, three parts; spirits of turpentine, three parts. Apply this to the tissue-paper with a brush and let it dry. To mount a print with tissue, lay the tissue on the mount and the photograph on the tissue, and rub the -whole with an iron just hot enough' to hiss when you touch it with a wet finger.