Sunday 8 May 2011

Somewhat Bowdlerized early pages from 'Faraday'.

Yes. I was afraid of this. The rather unimaginative, not to say near-illiterate, set-up of Google's blog-provider does not allow me to post the pages as I set them up, with marginal notes etc. I therefore offer a simplified 'text-only' version of a few pages; I fear even the footnotes have been lost this time. Clearly this system is not designed for people with any real interest in literature. Anyway, here it is:

Chapter I: From Faraday to Crippen
That he should need paperweights says something about a person, though now that so many people have computers and printers perhaps not as much as it did once. What he uses as a paperweight says more. No-one actually buys a paperweight as such. They use a Venetian or Lalique glass ornament; the worn-out piston from the old BSA Bantam; a pink stone from the beach; one of those water-filled globes that make a snowstorm.
Transformers – not the huge humming grey ones you’re not supposed to go near and that supply electricity to whole rows of houses, but the smaller ones you find in some kinds of old domestic electric equipment – make good paperweights, though that wasn’t what Michael Faraday had in mind when he invented them.
In the course of his electrical experiments Faraday noticed that a nearby compass needle would often flicker. It seemed to happen only when he made or broke the electric circuit; a steady current had no effect. Now a compass is a tiny magnet – could he get a converse effect? Placing a magnet near a wire didn’t do anything, but if he waved the magnet about an electric current was induced in the wire, and if he wound the wire into a coil and waved the magnet up and down in the space inside the coil the effect was greatly increased.
Conversely again, a coil of wire with a current flowing through it is one kind of magnet. Clearly, magnetism and electricity were closely related. But not very clearly. Putting a coil with a current flowing through it – an electromagnet – near another coil didn’t induce a current in the second coil. There was, however, a momentary burst of electric current in the second coil every time he connected or disconnected the supply to the first coil. Arranging for very rapid connection and disconnection – a kind of alternating current, like that in most present-day house wiring – could induce usable amounts of electricity (had there been any ‘uses’ for the stuff) in the second. And winding the two coils round opposite ends of a diameter of an iron ring made the thing work really well.
Faraday had invented the transformer, and incidentally refuted the adage that necessity is the mother of invention. Much later transformers became very useful indeed: electricity supplies all over the world are now almost always ‘Alternating current’ – in effect, being connected and disconnected a hundred times a second – because en route the electricity has been converted into magnetism, then back into electricity, in transformers. That’s why those big grey transformers hum, (The note is somewhere around A flat, 2½ octaves below Middle C) and the iron ring is why even the little one I use as a paperweight is heavy.

Anyone who would like to see the book, or what I have of it so far, in its proper format may e-mail me, and I shall send it to them individually, complete, in word format. simondarragh@hotmail.com

No comments:

Post a Comment