ON THE EFFECTS OF URBAN FOG UPON CULTIVATED PLANTS 151 



An ingenious person has suggested to me an alternative 

 method for excluding fog without interfering with ventilation, by 

 an arrangement of tricklers, such as one sees on ice factories in 

 summer for cooling. In this way a greenhouse might be com- 

 pletely enveloped in a thin mantle of dilute hydrogen peroxide, 

 permanganate of potash, or other absorbent, which could be 

 collected in gutters and pumped up again and again. A con- 

 siderable objection to this plan would be the liability of the 

 absorbent to freeze in cold weather, fog and frost being very 

 frequently concomitant. 



In conclusion, I have to thank my colleagues on the Com- 

 mittee for their constant help and sympathy. To my assistant, 

 Mr. F. E. Weiss, B.Sc, I am indebted for his continuous 

 devotion to the research ; without his aid the investigation 

 could not have progressed as it has. For the making of the 

 chemical analyses of injured tissues, &c, as well as for advice 

 on many questions of a chemical nature, I must thank my 

 former pupil, Mr. J. T. Leon, B.Sc, now Lecturer in Chemistry 

 at St. Mary's Hospital. 



