ofcy TRANSACTIONS OF SECTION A. 



compouent. The latter has its maxima at 10 a.m. and 10 r.ii., uiid the t,outLerly 

 component is about a quarter of a period in advance. Thus, to correspond with 

 the semi-diurnal -variation of pressure, there is a semi-diurnal variation iu the 

 Trade Wind at St. Helena, which is equivalent to the superposition upon the 

 resultant wind of a velocity-variation of about one mile and a half per hour, 

 passing through its zero value at half-past ten and half-past four, not far from 

 the hours when the extremes of the ellipsoidal deformation of the spherical 

 atmosphere are passing over the locality, together with a change of direction of 

 six degrees towards the southward between eleven o'clock and five, reversed 

 between five o'clock and eleven.' 



I have only dealt with one month. I believe that when all the results that 

 fiow from this simple statement can be put before you, you will agree with me 

 that the argosy which the Meteorological Council sent out in 1891 has indeed 

 richly come to harbour. 



Let me digress to say a word in illustration of the principle I laid down that, 

 if one would avoid waste in meteorological work, the observatious must be 

 examined forthwith and so far discussed that any ambiguities may be cleared up. 



After some years of wear at St. Helena the persistent rubbing of the south- 

 east part of the spiral metallic pencil upon the metallic paper wore away the metal 

 and left a flat place. This got so bad that the instrument had to come home for 

 repairs, and when it was set up again, after a year's absence, the average direction 

 of the Trade Wind differed by two points from the averages of most, but not of all, 

 of the previous years. So far as we know, the orientation has been attended to, as 

 before, and yet it is hardly possible to resist the suggestion that the anemometer 

 has been set slightly ditferently. We are now making very careful inquiries from 

 the observer ; but, in the meantime, it seems to me that there is a great oppor- 

 tunity for a competent mathematical physicist to help us. Dynamical explana- 

 tions of the Trade Winds have been given from the time of Halley. Let me offer 

 as a simple question in the mathematical physics of the atmosphere whether a 

 variation of two points in the direction of the south-east Trade Wind between the 

 years 190.3 and 1905 can be regarded as real, and, if not, which of the two 

 recorded directions is the correct one ? 



It would be appropriate for me to add some words about the results of last year's 

 work upon the upper air, in which we have had the valuable co-operation of the 

 University of Manchester. These results have disclosed a number of points of 

 unusual interest. But we are to have an opportunity of considering that subject in 

 a discussion before the Section, and 1 need not deal with it here. I must, however, 

 pause to give expression of the thanks of all meteorologists to Professor Schuster 

 for his support of the Manchester University station at Glossop Moor. I may 

 remind you that this generous contribution for the advancement of science on the 

 part of Professor Schuster is in addition to the foundation of a readership in 

 mathematical physics at Manchester and a readership in dynamical meteorology, 

 now held by Mr. Gold at Cambridge. 



I have said enough to show that the speculative ventures of official meteoro- 

 logists are not all failures, and I will only add that if any mathematician or 

 physicist would like to take his luck on a meteorological argosy he will be 

 heartily welcomed. Part of the work will be drudgery ; he must be prepared to 

 face that ; but the prospects of reaching port are reasonably good, so much so, 

 indeed, that such a voyage might fairly lead to a claim for one of the higher 

 academical degi-ees. 



Up to now I have been dealing with the adjustment of official scientific 

 work to reduce waste to a minimum, in so far as it lies within the control of those 

 responsible for an office. I turn now to an aspect of the matter in which we 

 require the assistance of others, particularly of the British Association. 



The most serious danger of waste in a busy office is that it should carry on its 



' This statement is a modification of that contained in the Address as originally 

 printed. The original was based upon a diagram reproduced in the Eeport of the 

 Meteorological Committee, 1908, in which the phase of the southerly semi-diurnal 

 component, is unfortunately incorrect. 



