PERSPIRATION 



4.VJ9 



PERTH AMBOY 



point of the system. Any system which van- 

 ishes upward will have the vanishing point 

 above the observer's eye; a system which van- 

 ishes downward will have the point below the 

 eye; the vanishing point of a system of hori- 

 zontal lines will be on a level with the eye, 

 and that of a system of vertical lines will be 



Level of Eye 



VR 



FIG. 2 



vertically in line with the eye. There are 

 similar rules for systems vanishing to the left 

 and to the right. All horizontal lines have 

 their vanishing points in the horizon. 



Consult Lubschez's Perspective: An Elemen- 

 tary Textbook ; Storey's The Theory and Practice 

 of Perspective. 



PERSPIRATION, pur spi ra' shun, a colorless 

 liquid secreted by glands in the skin. Over 

 niiu-ty-nine per cent of it is water, but it con- 

 - also small quantities of urea, sodium 

 chloride and other salts. Distributed over the 

 body are about two and one-half million sweat 

 glands, which, day and night, are discharging 

 i heir contents upon the surface of the skin. That 

 portion of the fluid which evaporates as fast 

 as it is secreted is known as insensible perspira- 

 tion; sensible perspiration is that which ac- 

 cumulates in drops. 



The amount of perspiration discharged varies 

 in healthy persons from twenty-five to seventy- 

 one ounces a day, but exercise and a high tem- 

 perature cause an increase in the amount se- 

 creted. In warm weather the evaporation 

 of large quantities of perspiration helps keep 

 the body cool. In health the flow of perspira- 

 tion and rate of evaporation are maintained 

 in that proportion needed to keep the tempera- 

 fun ,f the body at the normal point of 98 F. 

 When one has a fever the skin is dry because 

 the sweat glands are inactive. Profuse per- 

 spiration is sometimes brought about in treat- 

 ing kidney trouble, so that the sweat glands 

 may l>< 1; blood of the excess of urea 



caused by failure of the kidneys to work prop- 

 erly. Evaporating sweat leaves a film on tl..- 

 -km.:.:;; body should be bathed frc- 



qurntly to keep the pores open. See SKIN, 

 THE 



PERTH, purth, the capital of Western Aus- 

 tralia. It is situated on the north bank of the 

 Swan River, twel northeast of Fre- 



mantle, its port on the Indian Ocean. The 

 Darling Range of mountains towers on the 

 east, and the scenery in the vicinity has much 

 charm. Perth increased rapidly in population 

 during the last decade of the nineteenth 

 tury as a result of the discovery of gold. It 

 has two cathedrals (Anglican and Roman Catho- 

 lic), an observatory, the governors palace 

 and other notable public buildings, one of tin- 

 three mints of the Australian Commonwealth, 

 a park system and a race course. Population 

 in 1911, within a ten-mile radius from the 

 metropolitan center, 106,792. 



PERTH, a town in Ontario, the county town 

 of Lanark County, on the River Tay and the 

 Canadian Pacific Railway, fifty-two miles 

 southwest of Ottawa, 198 miles northeast of 

 Toronto and 140 miles southwest of Montreal. 

 Brockville is forty miles away; and Smiths 

 Falls, thirteen miles. The River Tay is navi- 

 gable only for canoes and small pleasure craft, 

 but the Rideau Canal, which has been ex- 

 tended to Perth, has aided materially in th. 

 development of the town. Perth's principal 

 industrial plants are foundries and machine 

 shops, sash-and-door factories, felt, carpets, 

 knitted goods, boots and shoes. There are 

 extensive mica deposits in the vicinity. The 

 town has a public library and a collegiate insti- 

 tute. Population in 1911, 3,588; in 1916, about 

 4,000. 



PERTH AM 'BOY, N. J., a port of entry in 

 Middlesex County, fifteen miles southwest of 

 Newark, on Raritan Bay at the mouth of th. 

 Raritan River. It has an excellent harbor and 

 is entered by the Lehigh Valley, the Pennsyl- 

 vania, the Central of New Jersey and the 

 Staten Island Rapid Transit railroads. 1 

 trie intcnirban lines extend to neighboring cities 

 and to the beach resorts of the coast. 

 population, which in 1910 was 32,121, was 41,185 

 (Federal estimate) in 1916. About forty per 

 cent of the inhabitants, consisting principally of 

 Hungarians and Slavs, are foreign born. The 

 area of the city exceeds four square miles. 



Perth Amboy has a fine water front on the 

 bay and enjoys a large commerce, ep< 

 coal. Trade is facilitated by the location here 

 of the terminal coal docks of the Lehigh Val- 

 ley Railroad. In the vicinity are found vast 

 deposits of fire clay from which arc manu- 

 factured terra cotta and bricks, and in th< 

 city are large shipyards and extensive copper 



