240 Master Minds of Modern Science 



When pure water splashes against a solid obstacle, electrifica- 

 tion ensues, and when a drop of water is broken up in the air 

 without striking anything, a similar separation of positive and 

 negative electricities occurs. In a thunderstorm there is a 

 region in which every time a raindrop breaks the water of 

 which it is composed receives a positive charge. A correspond- 

 ing negative charge is given to the air and is absorbed by cloud 

 particles which are being carried upward. The rain which falls 

 when the air-currents are vertical is thus positively charged, 

 while at a distance from this region it is negatively charged. 



The ceaseless search for new knowledge, of course, is 

 necessarily subsidiary to the practical aspects of the 

 Meteorological Office's work. Dr Simpson and his staff 

 know almost all that there is to know about that inex- 

 haustible topic the British climate. Ask them what the 

 weather was like at Birmingham at 2.30 on September 

 14th, 1901, and they can tell you. Or ask them to tell you 

 which is the warmest week of the average year at Black- 

 pool. They can tell you that also. 



Not long ago a Bill for stabilizing Easter was discussed 

 in Parliament, and it was suggested then that the weather 

 at Easter as it would be fixed by the Bill would not be as 

 good for holiday-makers as the weather of the present 

 movable Easter. At the request of the Home Secretary 

 the question was referred to the Meteorological Office. 

 The weather of the Easter week-ends during the past 

 hundred years was compared with that of the week-ends 

 on which Easter would have fallen if the Bill had been in 

 operation. The result of this investigation indicated that 

 as regards rainfall London would neither have gained nor 

 lost anything by stabilizing the date. On the other hand, 

 as regards sunshine and temperature, the fixed Easter 

 — coming later than do some Easters under the present 

 system of fixing dates — would have been an improvement. 



Here is another question which the Meteorological 

 Office helped to settle. When work began on the erection 



