SCIENCE SIFTINGS

New Zealand Tablet, 28 July 1921, Page 46

SCIENCE SIFTINGS

(By "Volt.")

Learned Monk First to Wear Spectacles. We have to go to Italy to locate the grave of the man who first struck the idea of aiding his failing eyesight with two lenses attached in front of his eyes by two wires hooking on behind his ears. His name was Spina. He was a learned monk who lived in Florence. While at work on a beautifully illuminated.missal, in 1285, his eyesight grew dim, and, intent upon finishing his task, he constructed the first pair of spectacles. The rest was easy for his fellow sufferers.

Saving Screw Shavings Two thousand years seems a long time to wait for an improvement, but this has been the case with the screw.

Metal screws have been made since 236 B.C. The shank pf the screw has been turned from a bar of metal having the diameter of the screw-head, thus wasting a large proportion of the metal by reducing it to shavings. A certain screw manufacturer has decided to alter this. A metal bar, of the diameter of the shank, is put into a matrix and subjected to enormous pressure. The head of the screw is thus expanded in the confined compartment, which gives it the desired shape. The only waste occurs in threading the screw and finishing the head.

Ever Heard of Clock Stars?

The Astronomer-Royal, Sir Frank Dyson, who has been elected senior warden of the City Guild of Clockmakers, is well qualified for the post. He it is who is responsible for our time, which is decided by the passage of certain stars, known as "Clock stars," over the incredibly thin spider's thread which, fixed in the focus of the transit instrument at the Royal Observatory, serves as the all-important Greenwich meridian. By electricity the master-clock at Greenwich automatically fires time-guns and drops time-balls in various parts of the country every day, and sends the hour of ten a.m. to all post offices and railway termini. The Greenwich clock is one of the most accurate in the world, but it is not quite perfect, and its "rate" is daily corrected by the observations made the previous night of the "Clock stars," unless clouds have hidden them. But if clouds prevented the correction of the Greenwich clock for a whole year, its error in that time would be barely five seconds.

• Fortunes Made By Accident. It was the burning of a starch factory that first revealed the adhesive qualities of scorched starch and introduced cheap gum. To the upsetting of a tool-chest we are indebted for cast-iron cement. The accident of a child playing with a bottomless oil-flask, which his brother, a Swiss mechanic named Argand, idly placed over the flame of his oil-lamp, gave birth to the lamp-chimney. Nobel accidently discovered dynamite and made a vast fortune, with which he founded the Nobel Prizes. The value of borax as a preservative was discovered by a traveller in Yellowstone Park, U.S.A. He found the body of a horse wonderfully preserved. It was lying in a borax dust and so a discovery which has been of boundless use in industry was made.

A boy of seventeen attended a "spirit-rapping" seance, and found that the table stood upon two brass rails run-vj across the stage. He suspected electricity. Taking a piece of insulated wire, the ends of which were open, he laid it across the two brass rails, and the "spirit" ceased to rap lears afterwards, this early experiment in track-circuidno-came to his mind, and he invented the automatic system' of signalling. Blotting-paper resulted from a batch of xaoer being made accidentally without size. It made a fortune for the lucky man.