THE EFFECT OF CEMENT DUST 



59 



than the low pulverizing- and drying mills; (3) chemical analysis 

 shows that the dust on the foliage has been partially burned. 



Amount of the dust. A simple "pulverometer," for collecting 

 and measuring the amount of dust, was made by supporting up- 

 right a large tin funnel (2 feet in diameter at the top) with a de- 

 tachable, tight-fitting, glass cjdinder at the bottom, into which 

 the dust collected or was brushed down from the sides of the 

 funnel. From the amount of dust caught in the cylinder (know- 

 ing the area of the mouth of the funnel) it is easy to calculate 

 the amount of dust that falls on an acre. An average record 

 (August 22, 1910) when the wind was blowing toward the pulver- 

 ometer, gave 167.6 pounds of dust deposited on an acre in twenty- 



TABLE II 

 Analysis of cemeni dust collected in the pulverometer Augtist 



Prof. Enrique Touceda 



1911. Analyzed by 



four hours, or 2^ tons of dust per acre in a month. But actuall}^, 

 no acre in the vicinity of the mills receives this amount because 

 the wind does not blow constantly from one direction. 



Chemical analyses. Numerous chemical analyses were made of 

 the dust collected as above and also of dust shaken from the 

 raspberry bushes a quarter of a mile distant from the mill. Av- 

 erage samples of these analyses are given in table I (samples 

 1442 and 1452). For comparison, there are also included in this 

 table analyses of (1) soil near the pulverometer, (2) average 

 sample of Portland cement, (3) two samples of road dust, No. 

 1453 a road dust sample taken at random near the mills, and No. 



