Science Siftings

New Zealand Tablet, 8 July 1915, Page 49

Science Siftings

By * Volt.’

Cement from Beets. It is now reported that a French firm is making an excellent cement from a by-product in the process of making beet sugar. The scum that forms when the beets are boiled, and which has heretofore been thrown away, consists largely of carbonate of lime and water, and from 70,000 tons of beet treated 4000 tons of carbonate of lime are obtained ; to this 1100 tons of clay are added, the resulting product being 3162 tons of excellent cement. The scum is pumped into large tanks, where it is allowed to dry partially; finely-divided clay is then mixed with it /Hie mixture is thoroughly amalgamated by beaters for an hour and burned in a. rotary kiln, much in the same way as Portland cement. The clinker is then removed and pulverised into cement. A Deadly Gas. Strange to say, bromine, which has been used with such deadly effect by the Germans on the battlefield, is not a gas at ordinary temperatures, but an exceedingly heavy liquid. When it is used in a chemical laboratory it is a. very heavy brown liquid, which begins to fume as soon as the stopper is taken out of its bottle. If the bottle is left open for a while the subtle brown vapor creeps over the edge and down the sides, finding it way slowly to the floor, and bringing death and destruction everywhere. It was first discovered in the waters of the Mediterranean Sea by A. J. Balard in 1826. Before he found it out the discovery had been made that ordinary sea salt contained chlorine, which must have been the most offensive gas known to science until Balard’s time, but bromine so far outdistanced chlorine in objectionableness- that its discoverer gave it the special name that it still possesses. Promos means ‘ a stink,’ so he called it bromine, and a stink it has continued to be ever since. Increasing the Heat of Coal. When the blacksmith desires the intensest heat of which his forge is capable he invariably throws a little water upon the coal. The same course is pursued by the stoker who would get the utmost from his boilers. And the poorer the quality of the coal the more imperative the necessity for wetting it. It seems paradoxical, for from the beginning all people everywhere have regarded water as the one reliable agency for extinguishing fire. Such, indeed, it really is, if used in proper quantity, as experience has amply demonstrated. Chemistry explains the paradox very simply, however, when it informs us that water is composed of oxygen and hydrogen in the proportion of two to one. That is to say, in every j molecule of the fluid there are two atoms of the former and one of the latter. Now, oxygen is the chief agent in combustion. Oxidization is a synonym for burning. The rusting of iron, the corrosion of silver, and the burning of wood are identical processes, all due to the agency of this powerful element, which is so widely distributed through all nature. To feed oxygen to flames is greatly to intensify them, therefore, this is exactly what is done, in fact, when they are fanned. Hydrogen, on the other hand, is a gas which burns readily and with the most intense heat. Very evidently, if water is separated into its constituent elements, the oxygen and the hydrogen, no longer bound together, are able each to perform its natural functions. The former adds greatly to combustion, and the latter not only burns readily, but materially intensifies the heat. This is precisely what occurs when a small quantity of water is added to the coal fed to the flames. There is not enough of the fluid to extinguish the fire. Instead, the fire acts upon the water, dissolving the bonds which unite its component gases, thus setting the oxygen free to accelerate combustion and converting the hydrogen into fuel of tremendous heating power.