556 



PEHR OLSSON-SEFFER 



least as far as 12 m. where they were intercepted by a white canvas 

 sheet. These distances are only relative values of the carrying capa- 

 city, as they show only what has been observed with the crude methods 

 employed; a number of grains are, no doubt, carried much farther 

 but cannot be distinguished on the sandy ground. 



IV. From about 8 : 15 a. m. the sand was drifting slowly, increasing 

 by degrees with the increase of force of wind and the rise of tempera- 

 "ture and consequent desiccation of the sand. Shortly after noon a 

 damp fog came driving inland from the ocean, and a decrease in the 

 movement of the sand was at once evident. A small shower of rain 

 followed and drifting ceased completely. Evaporation was not suffi- 

 cient to dry the sand during the rest of the day, and in spite of the 

 comparatively high wind no more drifting was observed. 



VI. Between 10 and 11 o'clock in the forenoon the separator was 

 at work, and collected samples of sand, the mechanical analysis of 

 which is given below. The sand was completely dry to a depth of 

 about 5 cm. and the separator was placed on ground sloping in an 

 angle of 25 degrees. 



PERCENTAGE OF DIFFERENT GRADES 



Diameter in mm. 



Floor A. — 0.02-0.05 

 o . 05-0 . I 

 O.I -0.2 



0.2 -0.3 



0.5 -I 



I . -2 . 



Floor B. — 0.02-0.05 



o . 05-0 . I 



0.1 -0.2 



o 



o 

 Floor C. — o 



o 



o 



o 



o 

 Floor D. — o 



Floor E.- 



.2 -0.3 



•3 -0-5 

 . 02-0 . 05 

 .05-0.1 

 .1 -0.2 

 .2 -0.3 

 •3 -0.5 

 . 02-0 . 05 

 o . 05-0 . I 

 0.1 -0.2 

 0.2 -0.3 

 -o . 02-0 . 05 

 o . 05-0 . I 

 O.I -0.2 

 0.2 -0.3 



Per Cent. 

 trace 



1.6 

 10.5 

 60.1 

 17.8 



6.7 



3-3 

 trace 



3-8 

 37-3 

 519 



7.0 



5-7 

 12.4 

 61.3 



14-5 



6.1 



21 .3 



63 -9 

 12.6 



3-2 

 64.8 

 28.6 



1-5 



