1894 



77-93 ; 



inches, 



1895 



88-43 





1896 



87-72 





1897 



103-18 





1898 

 1899 



92-15 

 90-44 





1900 



90-82 





Besiilts of Some Experiments upon tlie Bate of Evaporation. 47 

 temperature of the water. The results of seven years' observations. 



are- 

 Monthly Mean. 



January 10-42 inches. 



February 9*33 ,, 



March .' 7-22 „ 



April 4-80 „ 



May 3-80 „ 



June 3-10 ,, 



July 3-oS „ 



August 5-59 ,, 



Mean.. 90-11 ,, September 8-18 „ 



October 10-59 ,, 



November 11-73 ,, 



December 11-77 



I have not seen the Waterworks tank, but there is no doubt that 

 it could not have attained a higher degree of temperature than the 

 pan. The disagreement between the two is probably partially 

 accounted for by the sheltered position of the pan ; the wind being 

 interfered with a great deal by the trees. For the years 1897-8 

 at Kenilworth a circular iron tank of about 130 gallons 

 capacity, sunk in the ground, lost 81*75 inches and 68-92 inches 

 respectively. 



An analysis of some of the evaporation numbers derived from the 

 different Kenilworth gauges during the year 1900, furnishes a number 

 of details that are not without interest. A full account of the instru- 

 ments and of the results has been published elsewhere," so that it 

 will only be necessary to repeat just such particulars as are essential 

 for present purposes. 



In addition to (1) the copper pan mentioned above there are : — 

 (2) An iron tub, enamelled white inside and out, 20 inches high j 

 and 14 inches in diameter, standing with its rim about 2 feet 

 above the ground, and sheltered by a single-louvred screen. 



(3) A circular steel tank slightly less than 4 feet in diameter and 

 30 inches deep, standing in a cemented brick cistern of al)out 7 feet 

 square and rather more than 3 feet deep. Thus the level of the rim 

 of the tank is some 8 inches below the top of the cistern wall. The 

 tank is kept nearly full of water, and the cistern also contains water 

 up to about the same level. The indications are recorded by suitable 

 machinery upon a rotating drum. 



(4) A Piche evaporating tube of the usual pattern. 



(5) Pickering " evaporimeters." 



* Beport of the Metcorohxjical CommUmm for the year 1900 ; Cape Town,. 

 1901. 



f Outside dimensions ; the inside depth would be more than an inch less. 



