December 2 1, 1905 J 



NA TURE 



175 



"Mathematics : ' applied to Chemistry. 



In his notice of my book " Researches on the Affinities 

 of the Elements " in Nature, November 16, the reviewer 

 impugns the legality of applying mathematical formulae to 

 my surfaces. I trust I may be allowed to answer briefly 

 mv critic's objections. His difficulty as to the non- 

 continuous nature is imaginary, and arises from a mis- 

 taking of the object to be achieved — which is simply to 

 obtain either a surface or a mathematical expression from 

 which can be deduced the affinities any one element 

 exhibits for any other. This can be done from the 

 formulae, and they do, therefore, characterise the chemical 

 properties of an element which depend upon these affinities. 

 Although there exist an infinite number of points on the 

 surface which are occupied by no element, yet there exist 

 only a finite number of points the x and y coordinates of 

 which are whole numbers, and to every integer value given 

 to v and y in my formulae there corresponds a definite 

 element ; so that, so long as we keep within the domain 

 of integer numbers (as we are forced to do by the nature 

 of the construction) continuity is attained. 



The complexity of the formulae is more apparent than 

 real, because the only values which x and y can have are 

 integer numbers, and the constant and many terms dis- 

 appear in practice. Geoffrey Martin. 



Kiel, December 6. 



It is true that the plan proposed by Mr. Martin is 

 occasionally used on the convention that only the values 

 of the equations to the curve which occur at the integer 

 points are to be used ; but the reviewer still maintains that 

 the principle is a false one. A curve is intended to exhibit 

 continuous change, according to some law, and he is 

 unaware that any result of value has ever been obtained 

 by the use of the plan, except, perhaps, that of appealing 

 to the visual sense. The Reviewer. 



Heat a Mode of Motion in the Seventeenth Century. 



The following statement occurs in the " Medulla 

 Medicinae," by J. A. Van der Linden, Med. Prof., 

 Franekerae, 1642, p. 182 : — 



" Calor est minutissimarum materiae partium motus in se 

 reverberatus. " 



Van der Linden was a famous teacher, but the theory 

 may not have originated with him. Are there other 

 co-temporary anticipations of " Heat a mode of motion "? 



W. R. Gowers. 



THE PULSE OF THE ATMOSPHERIC 

 CIRCULATION. 

 COME fifteen years ago an American eclipse ex- 

 v -' pedition which included Prof. Cleveland Abbe 

 visited St. Helena, and, on leaving represented to 

 the Governor, Mr. R. L. Antrobus, now of the 

 Colonial Office, the importance of establishing a 

 meteorological observatory there. The representa- 

 tion was sent to the Colonial Office, and, the colonial 

 finances being then in a depressed condition, the 

 Colonial Office applied to the Meteorological Council 

 for assistance. 



It is needless to spend many words over the meteor- 

 ological importance of such an enterprise. St. Helena 

 emerges from the sea in the heart of the trade wind 

 of the southern Atlantic. In no part of the globe, 

 perhaps, is the trade wind current so persistent. The 

 trade winds have long been recognised as primary 

 factors of the atmospheric circulation. Speculation on 

 their origin, which still forms the staple of the 

 physical geography of the schools, carries us back 

 to the writings of Halley and Hadley. The south- 

 easterly current over St. Helena is the flow along the 

 main artery of the never-failing atmospheric circula- 

 tion, and at St. Helena if anywhere we may put our 

 finger on the pulse of that endless and complex pro- 



NO. 1 886, VOL. J$~\ 



cess of transformation of solar energy of which the 

 weather of our islands and elsewhere is an expres- 

 sion. 



The council, itself not wealthy, had a Robinson ane- 

 mograph, then lately returned from duty in Heligo- 

 land. This was lent to the colony, and with it was 

 found a small annual sum by way of payment for 

 its curator, Mr. Hands, of St. Matthew's Vicarage, 

 who undertook as well the duties of observer for a 

 normal station of the second order, with instruments 

 furnished by the council. 



The anemometer continued its run with some un- 

 avoidable interruptions, and the observations were 

 taken until the middle of 1904. There are besides 

 observations of rainfall at other stations in the island. 

 By 1904 that part of the spiral of the direction 

 pencil which had to record south-easterly winds be- 

 came so worn by constant use that a hollow was 

 formed there and the record had become an unsatis- 

 factory one. With the assistance of the engineer 

 officers stationed at St. Helena the matter was inquired 

 into, and. as a result, the instrument was ordered 

 home for repairs. At the same time an attempt was 

 made in the observatory branch of the Meteorological 

 Office to put together the results of the long run and 

 to collate them with the other observations. I will 

 not anticipate the publication of the results which, I 

 hope, will follow in due course, but to one interesting 

 side of them, too speculative for an official report and 

 too suggestive to be altogether ignored, I would like 

 to direct attention, because it shows a possibility (per- 

 haps more) that with more searching we may find a 

 working connection between the pulsations of the trade 

 wind in the southern hemisphere and the general type 

 of weather in so distant a part of the globe as our 

 own islands. 



While the trade winds may be regarded as the most 

 obvious representative of the dynamical effect of solar 

 energy, rainfall must be allowed to be also very closely 

 connected with the process of distribution of that 

 energy. The convection of heat by evaporation from 

 warm water surfaces and condensation in cooler 

 regions represents a process tending towards equalisa- 

 tion of thermal distribution on a gigantic scale. 

 The main directions of transference are from 

 south to north on the one hand, and generally east- 

 ward from sea to land on the other. The white snow 

 coverings of the polar regions and the persistent rivers 

 of great continents are permanent records of nature's 

 endeavour to distribute more nearly equally over the 

 globe the supply of solar heat. From a general point 

 of view rainfall or snowfall in the temperate and 

 arctic zones may be regarded as an index, perhaps a 

 spasmodic one, of the general circulation from the 

 tropical regions towards the poles, and to that ex- 

 tent as the counterpart or correlative of the kinetic 

 energy of the trade winds which represent the flow 

 towards the equatorial region. The transformation of 

 energy in rainfall is on a vastly greater scale than 

 that displayed by the trade winds. Supposing that 

 the trade wind at St. Helena is a mile high, the 

 energy represented by the year's flow in a slice of the 

 current a mile in width would be about equal to that 

 represented by a year's rainfall on a single square 

 mile in the neighbourhood of London. Of these two 

 indices of the general process of distribution of solar 

 energy, the one is the steadiest, the other the most 

 fluctuating of all meteorological phenomena, and any 

 indication of an underlying relation between them, 

 which is, in a way, a necessity of the general process 

 of circulation, would be of great meteorological in- 

 terest and might be of immense economic importance. 

 So far as I have carried it, the study is perhaps 



