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GUIDEBOOK OF THE WESTERN UNITED STATES. 



the mouth of Parleys Canyon, so named in honor of Parley P. Pratt, 

 the leader of the " First Immigration," or handcart companies. In 

 crossing the valley the traveler may obtain a good idea of its pro- 

 ductiveness, for here he sees all kinds of agricultural activities — 

 truck gardening, fruit growing, and live-stock raising. The area 

 passed through is largely suburban, with comfortable bungalows 

 embowered in shade. Just beyond the station of Sugar House is 

 the State penitentiary, on the left. 



From time to time in passing across this low land the traveler can 

 see the terraces back of the city, the State Capitol, the University of 



below that of 1850. The level of 1914 

 was 6 feet above that for 1905. 



" The land bordering the lake has 

 in many places a slope so gentle that 

 a small change in the height of the 

 water surface makes a great change 

 in the area of the lake. On a mup 

 completed in 1850 the area shown is 

 1,750 square miles ; on a map made in 

 1869 it is 2,170 square miles. In the 

 interval between the two surveys the 

 lake had risen 10 feet and this rise 

 enlarged the area about 24 per cent. 

 From the greater surface the evap- 

 oration was of course greater, and 

 the dependence of evaporation on area 

 is thus an important factor in regu- 

 lating the size of the lake. The effect 

 of a long series of wet years is some- 

 what reduced by the resulting increase 

 of evaporation surface, and the effect 

 of a series of dry years is lessened by 

 the resulting reduction of surface ex- 

 posed to evaporation. This natural 

 and automatic control limits the range 

 of oscillation and gives a certain per- 

 manence to what may be called a nor- 

 mal or average level. A change in 

 the normal can occur ^only when some 

 new factor is introduced. 



" Both man and nature have intro- 

 duced new factors and thus have pro- 

 duced changes in the normal level. 

 The occupation of the surrounding 

 region by white men has recently 

 modified the face of the land in ways 

 that have a recognized influence on 

 the water level ; and the ancient his- 

 tory of the lake includes eDormous 



modifications in response to changes 

 of climate. 



" Of human influences the most tell- 

 ing has arisen from the development 

 of agriculture with irrigation. In 

 irrigation the water of rivers and 

 creeks is diverted to cultivated fields, 

 which first absorb it and then through 

 evaporation feed it to the air ; and the 

 water thus consumed by utilization 

 is lost to the lake. With the gradual 

 enlargement of the irrigated area the 

 normal level of the lake is inevitably 

 being lowered, and engineers are al- 

 ready confident that the high-water 

 mark of 1877 will never again be 

 reached. On the other hand, there is 

 no reason to expect the lake's extinc- 

 tion, for there is a limit to the possi- 

 bilities of irrigation. 



" The fresh water brought by the 

 rivers mingles gradually with the 

 brine, and as the river mouths are on 

 or near the eastern shore the brine is 

 not so strong at the east as at the 

 west. Analyses of samples of the 

 brine gathered at different points and 

 in different years report the dissolved 

 solids as from 13.7 to 27.7 per cent by 

 weight. A sample taken in August, 

 1914, contained 18.9 per cent of solids. 

 At the present time the average salin- 

 ity of the lake is about 5J times that 

 of the ocean, and its density is 14.5 

 per cent greater than that of fresh 

 water. * * * 



"The brine is weakest in the north- 

 eastern arm. * * * This arm has 

 been partitioned from the main body 



