f RESIDENTIAL ADDRESS. ')9l 



the earth, and the suu. It waa the British Association which promoted the 

 establishment of magnetic observatories in many parts of the earth, and in the 

 early sixties secured the most brilliant achievements in the investigation of 

 the atmosphere by means of balloons. I know of no other opportunity of any- 

 thing like the same potentialities for the writers of papers to meet with the 

 readers, and to confer together about the progress of the sciences in which they 

 are interested. But its potentialities are not realised. Those of us who are most 

 anxious for the spread of the application of mathematics and physics to the 

 phenomena of astronomy, meteorology, and geophysics have thought that this 

 opportunity could not properly be utilised by crowding together all the papers 

 that deal with such subjects into one day, or possibly two days, so that 

 they can be polished oft" with the rapidity of an oriental execution. In 

 fact, the opportunity to be polished oft" is precisely not the opportunity that 

 is -wanted. There are some of us who think that a British Association week is not 

 too long for the consideration of the subjects of which a year's abstracts occupy 

 a volume of six hundred pages, and that, if we could extend the opportunity for 

 the consideration of these questions from one or two days to a week, and let 

 those members who are interested form a separate committee to develop and 

 extend these subjects, the British Association, the country, and science would all 

 gain thereby. I venture from this place, in the name of the advancement of 

 science, to make an appeal for the favourable consideration of this suggestion. 

 It is not based upon the depreciation, but upon the highest appreciation of the 

 service ^Yhich mathematics and physics have rendered, and can still render, to the 

 observational sciences, and upon the well-tried principle that close family ties are 

 strengthened, and not weakened, by making allowance for natural development. 



The plea seems to me so natural, and the alternatives so detrimental to the 

 advancement of science in this country, that I cannot believe the Association will 

 turn to it a deaf ear. 



The following Papers and Reports were then read :■ — 



' 1. Discussion on the Isothermal Layer of the Atmosnhere. opened hi 

 Dr. W. N Shaw, F.R,S, 



Dr. Shaw, in the absence of M. L. Teisserenc de Bort, opened the discussion. 

 He explained what was the main feature of the phenomenon, and showed how 

 it had been corroborated by ballons' sondes ascents made in England. The tem- 

 perature of the air decreases in the lower layers on the average at 5° or 6° C. per 

 kilometre up to a height of about ten kilometres. Above this height the tem- 

 perature ceases to fall rapidly, and falls very slowly indeed, or remains constant, 

 or in some cases increases. It had been suggested that the phenomenon might be 

 due to a change in the composition of the air at great heights. 



M. L. Teisserenc de Bort had succeeded in sending up balloons carrying 

 vacuum tubes, which were opened and re-sealed electrically at a height of fourteen 

 kilometres. The samples of air so obtained were examined spectroscopicallv, and 

 the examination showed that there was no change in the composition of the air 

 sufficient to account for the cessation of temperature diminution. 



It was intended that M. L. Teisserenc de Bort should open the discussion ■ but 

 he was unable to be present and sent the following communication : — 



' Permit me to open the discussion on the Isothermal Layer, and the inversions 

 of temperature which are found there, by recalling in a few words the results 

 obtained during the past twelve years. Our experiments at Trappes have shown 

 in the first place that the temperature ceased to diminish at a certain height after 

 liaving passed through a point of maximum rate of decrease about 3,000 metres 

 lower down. 



' The altitude at which the diminution ceases changes with the character of 

 the weather : it may descend as low as eight kilometres at Paris during a cyclone 

 wliile it rises as high as thirteen or fourteen kilometres in high-pressure areas and 

 in front of large cyclones. 



