Part 23 (2/2)

Describe the Mariner's Compass

The Mariner's Conetized bar of steel, called the _needle_, carefully balanced on an upright steel pivot, and having that end which points to the North shaped like the head of an arrow; attached to this needle, and turning with it, is a card on which are printed the divisions of North, South

East, and West; called the points of the co at the position of the needle, the , and regulate his helly

_Hel of a rudder and tiller

What is a Baroht of the ates of the weather, the height of lass tube hermetically sealed at one end, filled withto the weight of the atmosphere, this mercury rises or falls

How is the Heres of a vessel, till they are just ready to ether with hot pincers, so that the air may be totally excluded The word is taken from Hermes, the Greek na, and the supposed inventor of chemistry,[9] which is sometimes called the herypt, as either its inventor, or excelled in it

[Footnote 9: See Chapter XVIII, article Chemistry]

What is Mercury?

Quicksilver, or mercury, is a white fluid old; it readily combines with nearly all other lasses, barometers, thermometers, &c; in some of the arts, and in the preparation of several powerful ary, Sweden, Spain, China, and Peru The quicksilver mine of Guanca Velica, in Peru, is one hundred and seventy fathohty deep In this profound abyss are seen streets, squares, and a chapel, where religious worshi+p is performed The quicksilver mines of Idria, a town of Lower Austria, have continually been wrought forfrom the mercury is very hurtful to the ulf, a depth without bottom

In what state is Mercury usually found?

Either native, or in the form of ore; it is often found mixed with silver, but more frequently with sulphur in the for lobules, in America, and is collected from the clefts of the rocks

Mercury has the appearance of melted silver; it is neither ductile nor malleable in this state; it is a substance so volatile, when heated, that it may be evaporated like water; it is always seen in a fluid state, even in temperate climates, as a very small portion of heat is sufficient to preserve its fluidity It is used to separate gold and silver fron matter found with those metals Calomel, a valuable medicine, and vermilion, a color, are both preparations ofthe form of a ball or sphere

What is a Ther telass tube, terminated at one end in a bulb, usually filled with ree of heat or cold On the scale of the Fahrenheit ther point of water is rade and the Reau point at 100 in the Centigrade and at 80 in Reaumur's The invention of this instrument dates from about the close of the sixteenth century; but it is not known by whoht into use

_Terminated_, finished, ended

When and by ere Watches and Clocks invented?

Watches were invented about the year 1500, but as the inventor is disputed They were, however, of little value as ti as a regulator to the balance; the glory of this excellent invention lies between Dr Hooke and M

Huygens; the English ascribing it to the former, the Dutch, French, &c, to the latter Some assert that pocket-watches were first , in Germany The most ancient clock of which we possess any certain account, was made in 1634 by Henry de Wycke, a German artist; it was erected in a tower of the palace of Charles V, king of France The penduluens, in 1656

What is a Penduluht so suspended fro backward and forward; its oscillations are always perforth of the penduluravity re the pendulum for the measure ular oscillations of a lamp suspended from the roof of a church in Pisa It was not, however, till the ti itsthe number of its oscillations