an equinoctial and a solstitial armil, the graduated limbs of these instruments being divided into degrees and sixths.
There were in the observatory stone structures, the precursors of our mural quadrants.
On the floor a meridian line was drawn for the adjustment of the instruments.
There were astrolabes and dioptras.
The above were used from 246 B. C. to A. D. 417, and similar instruments at Cordova, A. D. 1000.
Tubes with sights were probably used at both places; lenses being added in 1608.
See articles under the following headings: —
Artificial Horizon.Mural Circle.
Azimuth Dial.Reflecting Circle.
Dr. Dee says (1570) that perspective glasses will enable a commander to ascertain the strength of an enemy's forces; referring apparently to an optical instrument then in use.
Leonard Digges (about 1571) appears to have been able, by proportional glasses duly situate, to discover things afar off, read letters and inscriptions on coins at a distance, and tell what was passing seven miles off. Such is the claim in his son's book, second edition, published in 1591.
Jansen (about 1608), a spectacle-maker of Middleburg, Holland, was struck by the effect of a concave and a convex lens held in the proper relation and distance.
For the purpose of observation, he fixed the glasses on a board in proper position, and afterwards in a tube.
He seems to have considered it interesting but not valuable, and Prince Maurice of Nassau became possessed of it.
Lippersheim, also of Middleburg, seems to have been concerned in it in some way.
Another claimant of the invention about th
Africa, doubling the Cape of Good Hope, November 20, 1497, testifies his surprise at meeting in the Indian Ocean seven small Arab vessels provided with the compass, quadrants, sea-charts, and other instruments, equal to the Portuguese.
We do not wonder, for the China seas had been navigated by their aid over 1,000 years when the brave navigator repeated the feat of the mariners of Pharaoh Necho, about 610 B. C.
The gimbal-joint and compass-box were invented by the Rev. William Barlowe in 1608.
The dip of the needle was discovered by Robert Norman of London, 1576; the diurnal variation, by Graham, a London watchmaker, in 1722.
An azimuth compass is one used at sea for finding the horizonal distance of the sun or a star from the magnetic meridian.
Lord Caithness has substituted for the gimbals a pendulum and a ball; the latter working in a socket in the center of the bottom of the compass-bowl.
Albini's self-registering compass is an instrument by which a continuous rec
d that the path of a ray of light through the atmosphere would be curvilinear, and the apparent position of the heavenly bodies an illusion.
He also determined the hight of the atmosphere to be nearly 58 1/2 miles. There were philosophers before Torricelli and Galileo.
The discovery of the lens is lost in antiquity, but in its early uses it was a microscope.
(See lens.) For telescopic purposes, a combination of lenses is required, — an objective and an eye-glass.
This was invented about 1608 by Lippersheim and by Galileo.
The latter turned it on the moon, and saw the shadows of the lunar mountains; on Jupiter, and discovered his satellites; on Saturn, and saw his bulging sides.
He supposed the planet to be triple, as his telescope was not of sufficient power to define the ring.
He afterward saw the phases of Venus and the spots on the sun. The reflecting telescope was invented in several forms, known as the Gregorian, Newtonian, etc. Then Newton made his discoveries in the ref
s matters, and obtain the fiber comparatively pure.
The usual course is to boil the stock in an alkaline solution.
The manufacture of paper from wood, straw, and various plants has been practiced for over a century, and reference is made under paper to three works of the last century whose leaves were made of various vegetable fibers other than cotton or linen.
A list of several hundred plants which have been used or whose use has been suggested is given in the same article.
See pages 1607-8.
Fig. 4008 shows an apparatus with a horizontal rotary tubular boiler having a fire-chamber C at one end, and a smokechamber at the other end. The fire-chamber has a roof, over which is a chamber communicating with a chimney.
The heat passes through the tubes in the boiler below the level of the roof, and into the above-mentioned chamber, and then passes through those above said roof, into the chamber, and then into the chimney.
The boiler rotates on bearing rolle
n tube, and made the first telescope ever used in the world, says Descartes.
The inventor was a suspicious character, and tried to keep the invention secret even on his deathbed.
But his brother and some few others had seen it, and were able to follow the track, which they opened to the world, and which was followed by Galilco.
The accidental discovery of the space-penetrating power of the telescope was first made in Holland, probably as early as the close of the year 1608.
According to the latest documentary investigations, this great invention may be claimed by Hans Lippershey (or Laprey), a native of Wesel, and spectacle-maker at Middelburg; Jacob Adriansz, also called Metius, who is said to have made burning-glasses of ice; and Zacharias Jansen.
Lippershey, on the 2d of October, 1608, offered to the States-General three instruments with which one can see to a distance.
On the 17th of the same month, Metius, in his offer to the States-General, states th