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The Alexandrians were also acquainted with the method ofdeducing the latitude from the sun's meridian altitude—forby close observations of the length of the shadow of thegnomon when the sun was on the meridian, the solstitialpoints were discovered, and the sun’s course, from one pointto the other, or its daily declination from the equator, wouldbe ascertained, which being added to or subtracted from themeridian altitude, would give the latitude required.

It is said that Eratosthenes of Alexandria , the successor ofAristarchus , about the year 200 B. C., determined the latitudeof Syenne in Egypt to be about 23° 30', by observing that adeep well received the vertical rays of the sun on the day ofthe summer solstice, without any perceptible shadow.

The ancient obelisks fonnd in Egypt and the east wereprobably used for astronomical purposes; and it is to theerection of gnomons in Italy , France , and other parts ofEurope , till the commencement of the seventeenth century,that we owe the foundation of all our astronomical know-ledge : but as practical astronomy advanced to accuracy andperfection, the shadow of the gnomon was found to begenerally ill defined, so that unless it was of a very consider-able height, the angle of elevation would not be sufficientlyascertained to insure an accurate result—to remedy thisinconvenience, graduated instruments, called quadrants, wereinvented, which marked the elevation of the object by meansof a plumb line ; and afterwards double mirrors were addedto the instrument, by means of which the image of thecelestial object was brought to the horizon, and its altitudemore correctly determined. ('See Quadrant.)

LAUREAT. Though the origin of the institution ofPoet Laureat in the King’s Household cannot be ascertained,yet, as Sir John Hawkins observes, there are many ancientrecords which notice it. In the reign of Henry III . therewas a court poet, named Henry de Avranches, who is sup-