Science Siftings

New Zealand Tablet, 4 November 1915, Page 51

Science Siftings

By ‘ Volt.’

What is a Pound ?

s It is interesting to recall that it is less than a hundred years since the gold coin known as the sovereign was declared to be of the value of twenty shillings. The proclamation declaring this to be its price current was issued on July 5, 1817. In 1489 pieces in value of twenty shillings, ‘to be called the sovereign,’ were ordered to be coined out of a pound of gold, but by 1550 they were passed as of the value of twenty-four shillings, and by 1552 they were passed as being of the value of thirty shillings. By the Coinage Act of 1870 the weight of the sovereign was fixed at 123.27447 grains troy.

Rest Cure for Razors.

Barbers tell us the razor gets tired and is improved after a rest. This is true in a scientific sense. It is not exactly a rest that the razor needs, although that term will express it pretty well. It seems that any razor, after constant use on the human face, will become not exactly dull, for the barber can sharpen it, but rather sluggish, and refuse to work as smoothly as when it has lain for a few weeks without wox'k. Constant use and coxxtixxued sharpening put the molecules in a sluggish condition, and it is impossible to get the same edge as when the steel has not been used for some time. When the razor lies idle and the electric current is passing off at the edges the particles are being toned and tempered, and the edge actually becomes more smooth and really sharper and more fit to remove the beard. It is claimed that a razor wrapped in rubber cloth and placed in a drawer away from any damp will not be as benefited by the rest as will a razor that is simply laid away rather carelessly without any isolation. It is the same if the razor is enclosed in a glass case, for the insulation prevents the electric current from passing through the metal.

Valuable Accidexxt.

When that very dangerous explosive, nitroglycerine, was first invented extraox’dixxary precautions had to be taken to prevent accidents while the substance was beixxg handled, but, notwithstanding this, so many disasters occurred that there seemed to be strong probabilities that its manufacture and use would have to be prohibited. After sevex’al Governments had actually interdicted its use, however, means were discovered by which this powerful explosive could be used with a minimum of danger to those who handled it. One of the methods employed was to convert the xxitro-glycerine into dynamite by its absorption in the infusorial earth known as kieselguhr. This process, however, involved a reduction of the explosive power of the nitro-glycerine, and explosives chemists persisted in their researches to find some substance which when added to nitro-glycerixxe would render it safe for handling without diminishing its explosive force. One of these chemists was Nobel. It is on record that one day while Nobel was at work in his laboratory he cut his finger, and in order to stop the bleeding he painted some collodion (a liquid preparation akin to guncotton) over the cut to form a protective artificial skixx. Having done this, he poured some of the collodion, by way of an experiment, into a vessel coxxtainixxg nitroglycerine, when he noticed that the two substances mixed and formed a jelly-like mass. He at once set to iwork to investigate this substance, and the outcome of these experiments was blasting gelatine, a mixture containing 90 per cent, of nitro-glycerine and 10 per cent, of soluble gun-cotton. Thus as a result of a very trivial occurrence that violent explosive blasting gelatin© was discovered.