Science Siftings

New Zealand Tablet, Volume XXXIII, Issue 36, 7 September 1905, Page 29

Science Siftings

By 'Volt*

Bees and Flowers. Bees are attracted to flowers by the bright colors. The experiments of Miiss J. Wery, a Belgian naturalist, prove that perfume has much less attraction, and that honey has none at all. Coal Tar Dyes. Experiments with fifty of the coal tar dyes have shown that fifteen are positively poisonous, and twenty others caused harmful disturbances of digestive organs, kidneys, or general health of amimals. Only two colors proved harmful to the skin. The most poisonous* colors are, not among the greens, though the noxious character of the arsenical greens has given that impression, but amomig! the coal-tar dyes the most seriously poisonous are yellow and orange colors, such as aurantia, m&nldarin, mentanil orange, and butter yellow. Next tn order of number are the blues, browns, and blacks, very few among the violet and green colors having proven at all harmful. New Source of Silk, A wearalfle silk fabric made from gelatine solution is manufactured in Glasgow with undoubted success. It can toe dyed any color, and takes all shades with a Twilliant lustre that rivals even that of natural sllik. The fibre is prepared by ejecting fine threads of a strong solution of a gelatine from very small orifices on to an endless band conveying them to bobbins, on which they are reeled. After leaving the srmall orifices'. the gelatine solidifies in a continuous fibre a thousandth of an inch in diameter, possessing a lustre even greater than that of a natural silk. The fibre in this state, however, is unsuitable for use, as it is easily spoiled by water. In order to render it impervious, it is waterproofed by a special process. A Lesson in Chemistry. An elderly man dropped into a well known chemist's a short time back, and produced a much ink-bespat-tered but originally cosily white shirt-front. ' Spilt the marking-ink over it,' he explained ; ' and I've just called to ask if you can get it out any way. I've heard it's possible.' ' Oh, yes ; certainly,' said the person addressed—' that is, if it is the ordinary marking-ink.' Artd taking the damaejod article of dress, he proceeded to eradicate the marks, explaining the method meanwhile. ' You see, all these inks are chiefly composed of nitrate of silver, and this solution,' pouring some liquid over the front and allowing it to lie in a tray— 1 is bichloride of mercury, usually 'known as corrosive sublimate, land its action is really to bleach the parts acted upon by the silver — same principle as intenisificat/iom, as practised in i^hotiography.' ' Er — yes. Just so,' said the interested watcher. In the space of a few minutes the chemdst, ha\'i'ng rinsed the solution out of the article, handed it limj) bait white to its owner. ' How much '' ' asVed that worthy. ' Twenty-five- cents, please,' was the reply. 'Too much,' remarked the gratified but ungrateful customer, laying fifteen cents on the counter. ' Just as you say, v returned the chemist, with affected carelessness. ' But I see there is one spot not erased yot. Allow me ' ; and he received the front back to remove the imaginary spot. ' You see,' he went on, faying it in another dish, and taking a bottle from the shelf behind him, ' the solution does not eradicate the ink, but "bleaches it ; and this,' he added blandly, pouring some liqiuid over it, 'is ammonia,* which instantly restores the spots to their previous blackness, with perhaps rather more intensity.' The ( Customer ' looked on in. dismay, while the chemist coolly rinsed the article and handed it back to him, with the remark : ' I am always pleased to< show these little experiments, sir, and if you wish to have those ink-stains removed again I shall^be happy to do so for one dollar. Won't have it done ? Well, giood morning, sir ' ; and, as the elderly sMinfli'nt left the shop in a towering rage, the man of drugs went behind his dispensing screen to enjoy a >quiet chuckle.