The Litchfield County post., 1828-01-24
EXTRACTS
From Arnott's General Philosop


 From Arnott's General Philosophy. MnutenesS of atoms of matter: Goldbeaters, by hammering, can re- duce gold to leaves so thin, that 262, ,OOO must be laid upon each other to produce the thickness of an inch; yet those leaves are perfect, or without holes, so that one of them laid upon any surface, as for gliding, gives the appearance of solid gold. They are so thin that if formed into book, make 1900 volumes, with upward oftour hundred pages m each.''
 Dlatation and contraction of substances by heat and colds :-
 DiLdtatiOn.-A rod of iron, which when cold, will pass through certain op- ening, and will lie lengthwise between two certain points. when heated becomes too thick and too long to do either. "For accurate measurement, therefore, the rods or chains used as the measure, must always be at the same temperature, ,or due allowance must be made for the diffe- renee.
 "The wall of a building had begun to bulge out so as to threaten its stability. No force tried could return it to perpen- dicularity, until the idea occurred of con- meeting it with the opposite wall with bars of iron; these were then heated alternate ly by lamps placed under them, and while heightened in consequence, nuts were screwed tight at their extremeties; SO that on again cooling and contracting, they pull led the pail back to its place. "The iron rim of a coach wheel, goes on loosely and easily, and when afterwards cooled, it binds the wheel most tightly ,giv- ing incredible 6rmness ahd strength.
 Porosity in bodies apparently solid :-
 "Bone is a tissue of shells and particles as little solid as heap of empty packing boxes.
 "Wood is congeries of parallel tubes like bundles of organ pipes. It has lately been proposed to prepare wood for some purposes, as for making the great wooden pins or nails used in ship building, by squee- zing it to halfits bulk between very strong rollers. 1t thus becomes nearly as strong as metal.
 A piece of wood sunk to a great depth in the ocean, and exposed to the pressure there has its pores filled with wa ter, and becomes as heavy as stone. Thus the boat of a whale fishing ship,which had been dragged far under water by whale, on being afterwards drawn up, was suppo- sed to be bringing up piece of rock with it."
 Elasticity =
 "Elas,Ic bodies vary much in the full extent to which they yield without break ing, and in the degrees of perfection with which, after the bendment or displacement of atoms, they return to the former state. India rubber is very elastic, for it yields far; but il is not perfectly elastic, flor when stretched much and often, it soon becomes permanently elongated. Glass, again, is perfectly elastic, for it will retain no per manent bend ; but, unless lu very thin plates indeed, it will not bend far without breaking.
 "An ivory ball, let fall on marble slab rebounds by its perfect elasticity nearly to the height from which it fell, and no mark is left on either. If the slab be wet, it is seen that the ivory had been good deal fattened at the point of contact, for con- siderable circular surface of the slab is found dried by the blow.-Biliard balls scarcely loose their polish by long wear,al-