RAINFORD 



6476 



RAINPROOF 



rain or very slight precipitation at 

 any season. Summer rains occur 

 either on the equatorial edges of 

 the hot deserts, as in the Sudan or 

 Rhodesia, or in the interiors of 

 continents, where the summers are 

 hot and the winters too cold for 

 any precipitation. Winter rains 

 occur on the polar edges of the 

 hot deserts, such as the Mediter- 

 ranean region, S. California, the 

 S. coast of Australia. Elsewhere 

 the rain is at all seasons as in the 

 equatorial regions, with two periods 

 of slightly heavier rains than the 

 average, or in the temperate 

 regions such as Britain, which has 

 a slight excess of rain in the late 

 autumn, and a deficit in the spring. 

 Rainfall is intimately related to 

 the main types of natural vege- 

 tation. Grass and scrublands are 

 drier than forests. Grasslands are 

 regions of summer rains. Winter 

 rain regions have characteristic 

 leathery -leaved trees, and usually 

 no grass. Most hill and mountain 

 slopes are forested. The study of 

 rainfall acquires practical im- 

 portance in relation to irrigation 

 schemes, to the suitability of a 

 district to a specific crop, and to 

 the question of the provision of 

 reservoirs for the water supply of 

 a big city. 



The Nile flood is due to summer 

 rains on the Abyssinian mountains, 

 the steady annual flow of Nile 

 water is due to the rainfall at 

 all seasons near the equatorial 

 lakes, Victoria, etc. ; these facts 

 were determined before the great 

 Nile dam was built. Areas suitable 

 for growing cotton, tobacco, rice, 

 and different types of wheat are 

 largely determined by the char- 

 acter of the rainfall. A water con- 

 servancy scheme to supply London 

 would involve calculations as to the 

 minimum rainfall during the driest 

 month, and the maximum during 

 the wettest month in the catch- 

 ment area of the proposed reservoir 

 or reservoirs. See England ; Mete- 

 orology ; Precipitation ; Weather ; 

 also colour plate, Rainfall. 



Bibliography. Atlas of Meteor- 

 ology, J. G. Bartholomew and A. J. 

 Herbertson, 1899 ; Distribution of 

 Rainfall over the Land, A. J. Her- 

 bertson, 1901 ; Distribution of 

 Rainfall in the U.S.A., B. C. Wallis, 

 The Monthly Weather Review 

 (Washington), January, April, and 

 June, 1915 ; The Rainfall of the 

 British Isles, M. 

 de C. S. Salter, 

 1921; British 

 Rainfall, pub. 

 annually. 



Rainford. 



Urban dist. of 

 Lancashire, Eng- 

 land. It is 4 m. 

 from St. Helens 

 and is served by 



the L. & N. W. and L . & Y. Rlys. It 

 is a rly. junction, and coal is mined 

 in the neighbourhood. Pop. 3,500. 

 Rain Gauge. Instrument used 

 for measuring the fall of water, 

 whether in the form of rain, hail, 

 or snow. A funnel, usually 5 ins. 

 in diameter, catches the rain and 

 leads it into some kind of vessel. 



Rainford. Seal of 



urban district 



council 



Rain Gauge. Instrument for mea- 

 suring rainfall. A. Collecting funnel. 

 B. Vessel which tips over when 

 0*1 in. of rain has fallen 



Negrelti & Zambra 



At fixed times the precipitation is 

 poured from this vessel into a 

 measuring glass, which is gradu- 

 ated to read very small amounts. 

 The graduations record inches or 

 mm. of rain, and depend upon the 

 capacity of the measuring glass in 

 relation to the superficial area of 

 the funnel in which the rain is 

 caught. To get correct results it is 

 important that the site of a rain 

 gauge should be carefully selected. 

 Many rain gauges are self-recording, 

 emptying themselves automatically 

 when full, and recording results on 

 a roll of paper on a cylinder. 



Rainier OR TACOMA. Quiescent 

 volcano in Washington, U.S.A. It 

 is situated in the Cascade Range, 

 alt. 14,363 ft. Fourteen glaciers 

 lie around its summit, and dense 

 woods clothe its lower sides. Its 

 crater emits fumes, but no recent 

 eruption has occurred, and its 

 eroded slopes indicate that there 

 has been no eruption for a con- 

 siderable period. 



Rain-making. Production of 

 rain by mechanical or other means. 

 Among primitive peoples many 

 usages and rites are practised for 

 the purpose. They may be mimetic, 

 as with the Australian Arunta 

 group, in which members of the 

 water-totem imitate a rising storm. 

 In New Guinea, Africa, and 

 America this is achieved by bull- 

 roarers, which the Navaho make 

 from lightning-riven pines, and the 

 Zuni accompany by frothy de- 

 coctions simulating cloud. Many 

 Amerind dances, especially in arid 

 regions, such as the Hopi snake- 

 dance, have a rain-making purpose. 



In some African tribes Bari 

 and Dinka, for example the rain- 

 maker is the local chief, using 

 magical stones and spears of tra- 

 ditional sanctity. Animal-sacrifice 

 is observed by the Akikuyu with 

 sheep and goats, and by the Buriat 

 with horses. Some N. Indian 

 forest-tribes immerse or sprinkle 

 old people ; in N. Africa a dressed- 

 up ladle, ghanja, is carried in pro- 

 cession and sprinkled ; the cere- 

 monial immersion of saint-images 

 survived into 19th century France. 

 In Burma temporary pagodas 

 were erected for rain-spirits in 

 human form, and after prayer 

 were thrown into the Irawadi. 



In modern times attempts have 

 been made to induce rain to fall, 

 chiefly by firing guns. In 1921 

 Charles M. Hatfield conducted 

 experiments, in which chemicals 

 were used, near Medicine Hat, 

 Alberta. The farmers were satis- 

 fied that these succeeded in pro- 

 ducing rain. 



Rainproof Cloth. Fabric 

 rendered more or less impervious 

 to rain without perceptibly affect- 

 ing its appearance, and without 

 filling up its pores with solid 

 material. The effect is dependent 

 upon a change of surface tension. 

 The material is treated in a way 

 which renders the adhesion between 

 the fabric and the raindrop less 

 than the cohesion between the 

 parts of the drop. Processes for 

 accomplishing this have been in 

 operation for some thirty years, 

 and silk, wool, and cotton cloths 

 are all dealt with. 



The methods most generally em- 

 ployed begin by divesting the 

 fabric of any grease it may contain, 

 and impregnating it with insoluble 

 oxides of alumina. The cloth is 

 then dried and treated with waxes, 

 an infinitesimally fine film or 

 smear of wax being applied either 

 in a molten condition or by rubbing 

 against a solid cake of wax. To 

 secure the best results wax of high 

 melting point should be used. 

 Rainproofing has been done by im- 

 pregnating the fabric with wax 

 dissolved in petrol or tetrachloride 

 of carbon. More objectionable 

 means have been used, such as a 

 mixture precipitation of lead salts 

 and soap, a combination prejudicial 

 to the health of the wearer, and of 

 loubtful efficacy as a protection 

 against wet. The treatment loses 

 part of its virtue in time, but the 

 rainproof property can be restored 

 by garment dyers. In wear the 

 cloths should be lined, as the in- 

 ternal friction of the body tends to 

 bring the rain through the inter- 

 stices. The most suitable goods 

 for ramproofing are those of a 

 close texture. 



