<;74 



MR JOHN AITKEN ON THE NUMBER OF DUST PARTICLES IN THE 



Table I. — The Number of Dust Particles in the Atmosphere for 1891 — continued. 









O CO 





, 



_>> 







Place. 



Date. 



Hour. 



Number 

 Particle 

 per c.c. 



Wind. 





B 

 W 



State of 

 the air. 



Remarks. 





Sept. 

















Alford 



15 



5.30 p.m. 



182 



N.W. 1 



54-5 



5-5 



Very clear 



Cloud I. 



)> 



16 



10 A.M. 



518 



S.S.W.0-5 



59-2 



4-2 



)j 



Cloud |- ; showers. 







6.30 p.m. 



182 



S.W. 2 



57 



4-5 



>> 



Cloud \ ; showers. 



>> 



17 



10 A.M. 



809 



E. 0-2 



53 



2 



Very thick 



Misty rain ; number 

 variable. 







1 P.M. 



550 



S.E. 0-2 



54-2 



2-2 



n 



Misty rain. 







6 P.M. 



588 



S.W. 0-5 



50 



1 



>> 



?i 



)> 



18 



10 A.M. 



231 



W. 2 



61-2 



7-6 



Very clear 



Cloud \. 







3 P.M. 



94 



)> 



60 



7 



Extremely 

 clear 



)> 







6 P.M. 



315 



)> 



55-2 



6-2 



>> 



Cloud \. 



)> 



19 



1 P.M. 



483 



S.W. 1 



58 



8 



Very clear 



Cirrus only. 







4.30 p.m. 



950 



WO-5 



57 



)> 



» 



Cloudless. 



» 



21 



9.30 a.m. 



570 



N.E. 4 



46 



1-2 



Very thick 



Cloud \ : heavy rain. 







4 P.M. 



474 



N.N.E. 4 



47 



2 



)> 



5) >) 







6 P.M. 



444 



)) 



46-2 



1-7 



!) 



5) )> 



3; 



22 



10 A.M. 



203 



N.E. 2 



48 



4 



Medium 



Cloud i. 







5 P.M. 



308 



E.N.E.0-5 



47 



3-5 



)> 



Cloud T V 



II 



23 



10 A.M. 



1,060 



S. 1 



49 



1-5 



Very thick 



Slight rain. 







6 P.M. 



2,850 



S.W. 1 



51 



3 



Thickish 



Cloud \. 



>J 



24 



10 A.M. 



5,100 



)> 



52 



2 



Thick 



Cloud i ; a few drops of 

 rain. 







1 P.M. 



3,550 



S.W. 3 



53 



3 



Very thick 



>> j) 







6 P.M. 



2,900 



S.W. 2 



50 



1 



?) 



Cloud \. 



JJ 



25 



10 A.M. 



1,025 



S.W. 0-2 



53 



5 



Clear 



Cloud i 







6 P.M. 



4,200 



S.W. 0-5 



54 



4-6 



Thickish 



Cloud \. 



II 



28 



10 A.M. 



392 



W. 2 



57-3 



4-3 



Very clear 



Cloud T V 







3 P.M. 



385 



W.S.W. 1 



63 



5 



jj 



Cloud J. 







6 P.M. 



925 



W.S.W. 2 



59-2 



3-2 



Clear 



Cloud I. 



)) 



29 



10 A.M. 



607 



W.S.W. 3 



55 



7 



Very clear 



Cloud f. 







1 P.M. 



497 



W. 4 



57 



8-5 



Extremely 

 clear 



Cloud Jj.. 



TABLE II.— The Number of Dust Particles in the Atmosphere for 1892. 





Feb. 

















Garelochhead 



17 



11 A.M. 



500 



N. 1 



32 



1 



Very clear 



Thin cirrus. 







12 



775 



>) 



35 



5 



>) 









4 P.M. 



900 



N.N.W. 2 



33-3 



4-3 



n 



Cloudless. 



J) 



18 



11.30 A.M. 



262 



N.N.W. 1 



30 



5 



Extremely 

 clear 



?s 







4.30 p.m. 



1,375 



N. 1 



29 



6 



)! 









5 P.M. 



950 



)) 



>> 



>> 



)) 



J? 







5.30 p.m. 



371 



)> 



28 



5-5 



)! 



jj 



»1 



19 



11.30 A.M. 



12.30 p.m. 



6,800 

 8,400 



S.E. 0-2 

 Variable 



29 



3-5 



Very thick 









3 P.M. 



5,100 



E. 05 



32 



2 



Thick 









5.30 p.m. 



5,900 



)> 



30 



4 



Thickish 









6 P.M. 



6,000 



>) 



)j 



>> 



JJ 





)> 



20 



11.30 A.M. 



785 



E.N.E. 3 



)> 



3 



Very clear 





