Random Readings.

Matamata Record, Volume III, Issue 165, 15 January 1920, Page 4

Random Readings.

♦ WHAT THE KALENDS WERH. Kalends, or Calends (from tho Greek kaleo, I ©all or proclaim), in tho ancient Roman calendar was the name given to the first day of every month. It was the day when the order of days was proclaimed; hc&'e, literally, proclamation-day. Every R»iuau month lmd three chief days: Kaloudae (tho Kalends), Nona© (the Nones), which fell on the fifth day of the mouth, excepting the months of March, May, July and October, when they fell on tho 7th; and Idus (the Ides), which fell'on the 13th or the 15th, according as the Nones wer6 on the oth and 7th. The Nones were «o called because they fell on the ninth duy before tha Ides, the Romans always including the first and last day in speaking of tho interval between any two days, lhose three days (the Kalends, Nones, and Ides) were taken as points from which the other day# were reckoned backwards; and any particular date wn# expressed by saying that it! was so many days before the Kalends, Nones, or Ides, as the case might be, the number, a# stated above, including the two extreme days. Thus, May 26th would bo the sixth day before the Kalends of June; June 10th would he the fourth day before the Ides (13th) of June; and July 3rd would-be the fifth day before the Noneß (7th) of July. The last day of any month was always called “the day before Kalends” of the succeeding month (pridie kal.). Interest fell due on the first day of every month; hence Horace speaks of that day as tristes kalendae (the sorrowful Kalandes); and a common expression among the Romans, which seems to partake of pleasantry, was solvere ad Graocas kalendas (to pay on the Greek Kalends), which really meant never to pay at all, there being no kalonds in tho Greek year. WHAT 18 GERMAN SILVER? German silver is a white alloy. Everybody knows that. But in answering tho above question a writer in “Things Technical” tolls us that it consists of nickel, copper,' and zinc, the best quality being made up of four parts zinc. This quality, however, is tho most difficult to work. It is known under probably a greater of names than any other alloy. In England and tho United States it is known as nickel silver, packfong, white copper, silveroid. Nevada silver and electrum. It is very ductile, and can be hammered, rolled, stamped and drawn. At the same time it possesses the properties of being hard, tough, and not easily corroded. Lead, iron, and tin are frequently found as impurities in German silver. Iron alloys perfectly with it, increasing the strength, hardness and elasticity of the alloy, at the same time making it whiter. Tin, on the other hand, does not ontor into the alloy in live same way as iron, hut forms a mixture which renders it brittle and unfit for rolling. Even when present in small quantities, it gives tho alloy a yellowish color. Lead does not alloy with German sflvor, hut separates out as metallic lead. W hen the alloy is to be cast and subsequently turned upon a lathe, from 2 to 3 per cent, of lead is added, a# it enables tho lathe to be worked at a higher speed and gives a better finish to tho work. German* silver is mado by melting the metals in graphite crucibles. In order to produce a more homogeneous alloy, and to lessen the oxidation of tho zinc, tho separate metals arc not melted together; but alloys of copper and nickel, and copper and zinc, are used, and shortly before pouring, a smnll quantity of zinc is added to overcome the effect of tho volatilation of the zinc and ensuro a thorough deoxidation of the alloy. The metal is cast in iron moulds previously heatod and coated with oil or mixture# of charcoal and oil or rosin and oil. The temperature of casting is a very important point. If the temperature is too high tho metal will he full of blowholes, and will crack In roiling. If, on the other hand, .it is cast at a low temperature, ft tends to 6olidi.fy as it touches the mould, with tho result that there is imperfect cohesion of tho metal. As the melting-point of German silver i# higher than that of brass, it must be cast rapidly, or tho crucible must bo returned to tho furnace and be reheated. If tho metal is to be rolled into sheets, moulds from 16in. to 18in. long, 4in. to Gin. wide, and lin. to 1 Jin. thick are used. When intended for wire, the moulds are 4 Jft. to sft. long, 3|in. wide, and ljin. thick. Gorman silver, beside# being used for many scientific instruments, is frequently used as a baso in cheap grades of silvor-plato ware. German silver, containing GO per cent, copper, 14 per cent, nickel, 24 per cent, zinc, and 1 to 2 per cent, tungsten, is used, under tho name of platinoid, for electrical resistances. It has also been alloyed with silver for jewellery and subsidiary coinage. Aluminium and magnesium have also been alloyed with German silver; hut, owing to the high cost, these alloys never found extended uso. German silver can bo readily soldered. The usual composition of German silver solder is: Copper 47 per cent,, nickel 11 per cent., and zinc 42 per cent. *