3655 



GRAVITATION 



welcomed here on 

 his accession to 

 the throne, and 

 Edward VII, 

 when prince of 

 Wales,landed 

 here with his 

 young bride, 

 Alexandra. 

 Gravesend's first 

 charter is dated 

 1562. In the parish 

 church of S. 

 George are mem- 

 orials of the 



Gravesend gives its name to a co. 

 div. returning one member to Par- 

 liament. Market day, Sat. Pop. 

 of mun. bor. 28,115. 



Gravimetric Analysis. Method 

 of obtaining the constituents of any 

 substance by weighing, as distinct 

 from volumetric analysis, which 

 obtains them by consideration of 

 the cubical contents. 



Gravina. City of Italy, in the 

 prov. of Bari. It stands on an 

 eminence on the left bank of the 

 Gravina, 29 m. direct and 63 m. by 

 rlv. S.W. of Bari. Over 1,000 ft 



gling. In 1779 he commanded a 

 sloop, and in 1781 was advanced to 

 post rank. He was in the action of 

 the Chesapeake, 1781, that of St. 

 Kitts, 1782, and of Dominica in 

 the same year. In 1800 he was 

 given a command under Lord St. 

 Vincent, and the next year was 

 promoted rear-admiral, sailing to 

 the Baltic under Sir Hyde Parker. 

 He was Nelson's second in com- 

 mand at the battle of Copenhagen 

 and was knighted for his services. 

 On his return he retired, and died 

 at his house near Honiton in 1814. 

 Grave's Disease. Alternative 

 name for the disease known as 

 Exophthalmic Goitre (q.v.). 



Gravesend. Parl. and mun. 

 bor., river port, and market town 

 of Kent, England. On the right 

 bank of the Thames estuary, 24 m. 

 E. of London by the S.E. & C. and 

 L. & T. (M.) Rlys., it is opposite 

 Tilbury, with which there is ferry 

 communication. It is a customs 

 and pilot station, a port under 

 the Port of London Authority, and 

 the headquarters of the Royal 

 Thames Yacht Club. The market, 

 owned by the 

 corporation, has 

 existed since the 

 close of the 13th 

 century. The 

 town has electric 

 lighting works, 

 town hall, a 

 library, and, in 

 the Imperial 

 Paper Mills, 



Gravesend arms 



Ltd., the second largest and the 

 most modern business concern of 

 its kind in the United Kingdom. 

 The frontage of the paper mills is 

 directly on the river, and there is 

 a jetty opposite the main entrance, 

 so that ocean steamers can unload 

 their cargoes of wood pulp within 

 a few feet of the paper-making 

 plant. Close by is a branch printing 

 office of The Amalgamated Press. 

 Gravesend has a history going 

 back to pre-Norman times. In 

 1380 the town was partly burnt 

 by the French, and it shared in the 

 Wat Tyler rebellion. George I was 



Gravesend, Kent. The works of the Imperial Paper Mills, Ltd. Top, left, the 

 Jubilee Clock Tower 



Indian Princess Pocahontas (.#.), 

 who saved the life of Captain 

 John Smith (q.v. ). There are two 

 piers. Rosherville Gardens, 1 m. 

 to the W., were once a popular 

 resort for Londoners. 



Shipbuilding, brewing, and shrimp 

 fishing are among the industries, 

 while vegetables and fruit are 

 grown in the surrounding districts. 



above sea level, it possesses a 15th 

 century cathedral, a castle of the 

 Emperor Frederick II, afterwards 

 belonging to the Orsini, and me- 

 dieval walls and gateways. Besides 

 Santa Sofia, there is a rock-hewn 

 church, with ancient paintings. In 

 the vicinity are prehistoric tumuli, 

 and a castle of the Hohenstaufen. 

 Pop. 19,900. 



GRAVITATION: THE UNIVERSAL LAW 



W. D. Evans. M.A., King's College. Cambridge 



This article discusses the general conception of gravity and the theories 



which have been formulated to explain it. See also the articles 



Ether; Matter; Relativity 



Gravitation (Lat. gravitas, weight) 

 is the universal law governing the 

 motions of all material bodies. 



The simplest manifestation of 

 gravitational force is the property 

 of a body known as its weight, in 

 virtue of which it falls to the earth, 

 or if supported, exerts a down- 

 ward pressure. When the earth 

 was conceived as flat, the weight 

 of bodies was interpreted as the 

 result of a natural tendency 

 " downwards," but when the idea 

 of the spherical form of the earth 

 was accepted, it became clear that 

 the direction which was " down- 

 wards " for one place on the earth 

 was " upwards " for the antipodes, 

 and that the natural tendency was 

 for bodies to fall towards the centre 

 of the earth. The fall was not 



necessarily direct, as a body might 

 evidently fall in a curved path. 



Gravitation as a general law 

 was advanced by Sir Isaac Newton 

 as a mechanical explanation of 

 the paths of the planets around 

 the sun. Newton showed mathe- 

 matically that these paths could be 

 accounted for by ascribing to the 

 planets a tendency to fall to the 

 sun, similar to the tendency to fall 

 to the earth which is observed in 

 bodies on the earth's surface, and 

 he proved that this tendency to 

 fall varied in intensity inversely as 

 the square of the planet's distance 

 from the sun. He assumed the exist- 

 ence of an attraction exerted by 

 the sun on the planet, and likewise 

 varying as the inverse square of 

 the distance; and this attractive 



