Obelisk
2 of the 7 encyclopedias on this shelf carry an entry for Obelisk. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
in printing and writing, in its Latin sense, a sign like a sharppointed spear (!) with which doubtful passages were marked, or references made to notes in the margin, or at the foot of a page; a dagger. In architecture, a slender stone that, with quadrangula pyramidal apex. The width of the base is usually about one-tenth of the height, and the pyramidal apex has about one-tenth of the whole length. Obelisks were commonly formed from a single stone, mostly of granite. Obelisks were erected in pairs, and many still exist on the ancient sites, while others have been removed and set up elsewhere. The obelisk was the Egyptian symbol of the supreme God. The Arabians called them Pharaoh's needles, and the Egyptian priests the fingers of the sun. The first obelisk is said to have been erected by Rameses, King of Egypt, in the time of the Trojan war; it was 40 cubits high, and employed 20,000 men in building. There are about a dozen Egyptian obelisks erected in Rome. One was erected by the Emperor Augustus in the Campus Martius, on the pavement of which was a horizontal dial that marked the hour, about 14 B. c. Of the obelisks brought to Rome by the emperors, several have been restored and set up by various Popes. The largest is that from Heliopolis. It is of granite, and now stands before the N. portico of the Church of St. John Lateran, where it was erected in 1588. Its whole heigh is about 149 feet; without the base, 105 feet. It was removed to Alexandria by Constantine, and to Rome by his son Constantius, and placed in the Circus Maximus. The obelisk at Luxor was presented to the French nation, in 1820, by Mehemet Ali, and was re-erected in Paris in 1833. Its height is 73 feet. The obelisk presented to the English nation was removed to England and set up on the Thames Embankment in London. Of Egyptian obelisks 42 are known, some broken; 12 at Rome; 1, from Luxor, set up in the Place de la Concorde, Paris, October, 1836; 5 in England; 1 in Central Park, New York. The obelisks improperly named "Cleopatra's Needles" were erected by Thothmes III. at On (Heliopolis), about 1600 b. c. One was removed to Alexandria by Augusta, about 23 b. C. The Washington obelisk at Washington is 555 feet high, and was dedicated Feb. 22, 1885. The Bunker Hill Monument may also be properly called an obelisk, and that with the Washington are the two most famous of American construction.
Aiton's Encyclopedia (1910)
a kind of stone monument peculiar to Egypt. It consisted of a single piece of red granite from the quarry of Syene in upper Egypt. Egyptian obelisks vary from a few feet to sixty-six feet in height. They are usually square in section and taper upward gradually, terminating in a pyramidal cap. They were chiseled from the solid rock. Three faces, that is to say, the top and two sides, were polished as the block lay in position in the quarry. Holes were then drilled and plugs of wood were driven in. These pieces of wood, upon being moistened repeatedly, swelled and acted like wedges, splitting off the stone its entire length without breaking it. The fourth side was then finished. The obelisk was conveyed down the Nile on a raft during the period of high water or else it was conveyed on a rude log cart dragged by men. Upon reaching their destination, the obelisks were inscribed with the facts of Egyptian history or the exploits of the Pharaohs. The letters of the inscriptions are in columns, reading from top to bottom instead of crosswise. Many of these obelisks were erected at Thebes. The largest were set up at Heliopolis. The list includes about forty. A number were transported to Rome; one stands on the embankment in London. A similar, indeed a companion, monolith, known as Cleopatra's Needle, was conveyed from Alexandria, Egypt, to Central Park , New York , and set up in 1880. The Washington Monument at Washington, D. C., and the Bunker Hill Monument have the obelisk form. They are composed, however, of regular courses of masonry. See Central Park