438 REPORTS ON THE STATE OP SCIENCE. — 1919. 



to red. The instrument is illustrated diagrammtically. It will be seen that 

 the colour change in the observation tube can be measured in units of depth of 

 liquid in the tintometer tube, and it only remains to calibre the latter to provide 

 a measure of the acidity. Methyl orange as an indicator has the advantage 

 that it is not sensitive to CO^, which is a noiTnal constituent of the air. 



1 will not delay you further by a technical description of the ditliciilties 

 encountered in this investigation, as they will be fully described in the Com 

 mittee's Report ; but I may say that the measurement of the acidity of the air 

 was taken in hand at the express wish of the Department of Scientific and 

 Industrial Research. 



In concluding, there are two special points which I wish to lay special 

 emphasis upon. The first of these is the need for further observing stations, 

 not merely in cities, but in places where there is believed to be little pollution of 

 the air, such as seaside health resorts. It is very important to know what 

 standard of purity we may expect in the air. I feel sure, also, that in some at 

 least of our health resorts, which have developed into large cities, the air 

 would be found to be coneiderably polluted. 



The second point is the need at this stage for extending the work of investi- 

 gation and measurement so as to include not only the nature and degree of 

 pollution but means for prevention. I suggest that this be dealt with from the 

 present point of view rather than as a side-issue of a fuel-economy research. 

 Incomplete combustion is a chief source of impurity, but there are other sources 

 to be considered, such as road dust, chemical fumes, destructor fumes, and the 

 like, and it has also to be remembered that from a fuel-economy point of view 

 alone it might not pay entirely to do away with smoke. 



Mr. T. Sheppaed (Hull Scientific and Field Naturalists' Club) referred to 

 the conditions obtaining in Hull. 



Sir Napier Shaw (Director of the Meteorological Office) pointed out that 

 Dr. Owens had not represented fully the sei^vice which the Advisory Committee 

 for Atmospheric Pollution had rendered to the community, and particularly 

 had omitted to notice the extent of liis own share. The standard gauge was 

 criticised by persons accustomed to laboratory work because it only represented 

 the atmospheric pollution collected during the month. But the standard gauge 

 represented the first practical attempt to measure the amount of pollution that 

 falls in an open space, and as a first contribution it is of great value, although, 

 like all other observational work, it does not necessarily answer precisely the 

 question one would like to put. The automatic filter, which was taken in hand 

 spontaneously by the Committee at the same time as the standard gauge, is 

 now completed according to Dr. Owens' original designs, and may be recom- 

 mended for inspection as a masterpiece of ingenuity. The research in acidity 

 was conducted by Dr. Owens with an assistant, Mr. Watson, who was trained 

 at the Imperial College of Science. The chief part of the work of the CJom- 

 mittee is carried out by Dr. Owens with valuable assistance in the technical 

 details of the chemical processes used in analysing the products. 



Mr. T. W. SowERBUTTS (Manchester Geographical Society) asked whether 

 the increase of pollution during the past four years might not have been due 

 to a considerable extent to the great difiiculty during the War which manufac- 

 turers and other users of coal have experienced in obtaining the fuel most 

 suitable for their requirements, with the result that much unoonsumed smoke 

 has been allowed (partly through the leniency of magistrates) to vitiate the 

 atmosphere. 



Professor Lea said that not enough pressure was put on to the users of fuei 

 who would get more power and economy under scientific control, while pollution 

 would be lessened. He gave an instance where the services of a scientific 

 student were put at the disposal of a paper mill, with the result that five 

 thousand pounds worth of coal was saved in one year. 



Dr. J. R. ASHWORTH (Rochdale Literary and Scientific Society) refei-red to 

 the enormous deposit from the atmosphere which takes place in Rochdale, 

 amounting to nearly one thousand British tons per square mile in the course of a 

 year, and pointed out that it \yas likely that a good deal of this might be 

 carried into the town from South-East Lancashire by the prevailing west winds, 

 the Pennine Hills to the east of the town, acting as a barrier to passage of 



