274 Dr. P. F. Frankland and Mr. T. G. Hart. 



Number of 

 ; micro-organisms 

 falling on 

 1 horizontal 

 square foot 

 per minute. 



CO 



i> 



<N 



CO 

 rH 



00 

 00 



203 (little wind) 

 798 (more wind) 



o 2 

 m ^ J> o tfs 



S f> CO CO H 



o © 



00 CM 

 rH <M 



Number of 

 colonies from 

 10 litres of air 



(calculated) . 



(28?) 





o 



CO 



00 



o 



rH 



<M 

 X> 



Number of 

 colonies 

 obtained from 

 given volume 

 of air. 



(33 in 12 lits.) 



59 in 12 lits. 



72 in 12 lits. 



129 in 12 lits. 



86 in 12 lits. 



Conditions of experiment. 



Wind N.W., moderate. No previous rain. 22 '2° C. The 

 number of colonies in the tube is only approximate, owing 

 to the growth of a large liquefying colony. 



Wind N.E. by E., strong. No previous rain. 17 "5° C. 



Wind S.W., slight. Considerable rain during preceding 

 night. Roads, &c, quite wet during the morning, but 

 drier at time of experiment. Slight rain during experi- 

 ment. 21° C. 



Wind S.W., very gentle, but increasing considerably at end 

 of experiment, when it changed to W. by N.W., and blew 

 much dust about. 26° C. 



Wind S.W., gentle, but variable, both in strength and 

 direction. No previous rain, but roads well watered. 

 22 -5° C. 



Date. 1886. 



si's 



00 Ph 

 if 1 



OS Ph 



|1 



co 



July 12th. 



12—1 P.M. 



July 21st. 

 4.18—5.20 p.m. 



& 



rH 



