May 26, 1881] 



NATURE 



93 



THE SECULAR INEQUALITIES IN TERRES- 

 TRIAL CLIMATES DEPENDING ON THE 

 PERIHELION LONGITUDE AND ECCEN- 

 TRICITY OF THE EARTH'S ORBIT 

 A PAPER on this subject, by the Rev. Dr. Haughton of 

 ■^ Trinity College, Dublin, was read before the Royal Society 

 on February 24 last. Dr. Haughton shows that the two in- 

 equalities in question depend upon terrestrial radiation only, and 

 in no way upon sun heat. 



Having noticed that the hottest and coldest time oi A3.y follows 

 noon and midnight by an interval often considerable ; and in like 

 manner that the hottest and coldest days in the year follmu mid- 

 summer and midw inter ' by an interval often of many days ; Dr. 

 Haughton saw in these facts a close analogy with the diurnal 

 tides, which follow the sun or moon's meridian passage by an 

 interval of some hours. 



Dr. Haughton was thus led to solve the differential equation 

 on which the problem depends, by assuming an expression similar 

 to those so well known and so long employed in the mathematical 

 discussion of the tides of the ocean. 



The result fully justified the assumption of expressions similar 

 to diurnal tidal expressions, for when the differential equation is 

 integrated for a day and summed for a year, all the periodic 

 terms disappear, and nothing is left but terms depending on the 

 perihelion longitude and eccentricity, which represent the exact 

 mathematical expression of the two inequalities first noticed by 

 Adhemar and CroU. 



The final result takes the form — 

 Mean annual temperature 



= /((ej + (7) ± (ajCOS a + /3i sin5))d-) . . (l) 

 where 



k, — Constant, 

 00, = Mean annual temperature of place, 

 a, = " Control "" temperature of atmosphere at place. 

 a, and flj are defined by the following equations : — 

 2 ^ Oj- + j8j- — Range of annual temperature. 



a ("Tangent of the arc which represents the 



^' — ' retardation of the maximum and minimum 



"1 y temperature. 



w — Longitude of earth's perihelion. 



e — Eccentricity of earth's orbit. 



Using Ferrel's temperature tables. Dr. Haughton finds the 

 following maximum secular ranges of mean annual temperature : — 

 Maximum Secular Range 

 Latitude. Northern hemisphere. Southern hemisphere. 



o o-i°85 F o-i°8s F. 



'o o"37S , o'S-'^S .. 



20 I'loo ,, o'S75 >> 



30 2'o6s „ iiio ,, 



40 2750 ,, 0-985 ,, 



50 3"685 „ 0710 ,, 



5o 4'6lo ,, ... ... 0'540 ,, 



70 4"9S5 ,, — 



80 4-925 ,, — 



This table shows that the average maximum effect of the astro 

 nomical causes involved in perihelion longitude and eccentricity 

 never can exceed $° F . in the northern hemisphere, and barely 

 exceeds 1° F. in the southern. At particular localities, where 

 there is a great range of annuil temperature, the effect may he 

 somewhat greater. For example, at North Grinnel Land the 

 range becomes 6°-5 F. It will be seen how little benefit this 

 would confer upon that locality, when it is remembered that the 

 present mean annual temperature of North Grinnell Land is 

 2° '42 F. belimi zero, and that by the secular range it could be 

 raised to o°-2i F. above zero, or depressed to 6° -29 belozo zero. 



At Discovery Harbour Tertiary plant beds were found by the 

 Arctic explorers, which indicate a July temperature greater than 

 (>S°'7 F. ; the present July temperature of Discovery Harbour is 

 37° -2 F. above zero, or on'y five degrees above the fretzing point 

 of water. How is this remarkable change in climate to be 

 accounted for ? Geologists cannot much longer evade answering 

 such questions as these. 



' In the British IsLinds January 15 is reckoned the time of maximum cold, 

 which is twenty-four days after midwinter. 



' By this is meant the temperature of the upper layers of thj atmosphere 

 of place, which controls the radiation ; this temperature varies with the lati- 

 tude, and is probably always below lero Fahrenheit. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 

 Cambridge. — The Cambridge Museums are every year the 

 scene of a large increase of work, new departments being con- 

 tinually added, even under the present conditions of impecuni- 

 osity. The annu.il reports recently issued on the condition and 

 progress of all the de|jartnjents testify to much excellent work. 

 The death of Prol Miller, who for forty-nine years occupied the 

 Chair of Mineralogy, has brought a valuable bequest to the 

 museum he jiresidcd over, in the shape of 300 volumes of books 

 and many specimens and scientific instruments, including his 

 famous gon'ometer and the physical ajiparatus, balances, ther- 

 mometers, and barometers employed by him in his investigations 

 for the restoration of the standards of weight. Prof. Lewis, 

 who has succeeded to the Chair of Mineralogy, ably assisted by 

 Mr. Solly, is cataloguing the museum, and already half the work 

 is accumpli hed. Valuable specimens besides Prof. Miller's 

 bequest have been added to the museum by purchase as well as 

 by donation, including a small case of minerals belonging to the 

 late Dr. E. D. Cbrke, given by the Rev. B. S. Clarke, Boxted, 

 Colchester. Prof. Lord Raylsigh's Apparatus Fund has reached 

 2025/., including 500/. from himself, which has been spent 

 partly upon iustruments required to be multiplied, in consequence 

 of the increa ed number of s;udents ; but the additions during 

 the year also comprise a large electro-magnet with heavy 

 glass and nicol ; a 24-inch achromatic telescope ; Joule's 

 apparatus for investi^;ating the maximum density of water ; 

 telephones and various optical apparatus, including new 

 double refractive apparatus for combining prismatic colours. 

 Many important pieces of apparatus have been made for 

 the Cavendish Laborat.iry in Prof. Stuart's laboratory. Pro- 

 fessors I.iveing and Dewar report that with the 200/. alloted to 

 them they have purchased several pieces of apparatus per- 

 manently useful in a variety of inve.-tigations. Prof. Stuart's 

 department (mechanism) has prngrc-ssed very considerably during 

 the year. The apparatus, machines, tools, and materials in 

 ctmiiection with the de[>artinent have been recently valued at 

 over 1500/., of which only about 250/. is University property, 

 the re t having been provided by the private enterprise of Prof. 

 Stuart. In the Geological Museum, d-spite the want of suitable 

 workroonjs, Mr. Tawiiey has succeeded in arranging the petro- 

 ls igical collection. Mr. Keeping reports the addition of many 

 im|>orta t fossil specimens both from England and America. 

 Prof, iluinphry reports further additions to the rich collection 

 of human skulls undei his charge. Mr. J. W. Clark, Superin- 

 tendent of the Museum of Zoology and Comparative Anatomy, 

 calls special attention to the beautiful coloured drawings of 

 animals that cannot be preserved in spirit, or are too small to be 

 seen without a microsc pe, added by Prof. A. C. Haddon, late 

 Curator in Zoology. His successo", Mr. A. H. Cooke, Fellow 

 of King's College, has ciminenced the work of determining and 

 catalnuuin^ the Woodv\ard and Hepburn collections of shells. 

 Mr. Clark has added a series of iireparations showing the struc- 

 ture ot the manatee, from a specimen presented by the Directors 

 of the Hrii^hton Aquarium. 'I'he very 'ine skeleton of the musk- 

 ox brought home by the North German Polar Expedition of 

 1872 has been purchas-d. The skeleton of Ccratodus Forsteri, 

 from the specimen presented by Prof. Liversidge, has 

 been preiiared in the museum. Many additions have also 

 been inarie to the rcf tilian, ornithological, and other series. 

 Dr. Michael Foster notes th;it his classes for histological work 

 have become so large that a new bench, less convenient as to 

 light, has i.een adoed. The numbers attending his courses are 

 betueen sixty and seventy men and twenty women for the ele- 

 mentary classes, and fifteen men for tlie advanced clxsses. He 

 remarks that his students would profit more if not so much 

 harassed by striving to attend too great a number of lectures 

 and courses. Prof. Babington records a large amount of 

 herbarium work, including the naming of Gardner's collection of 

 Brazilian plants, numbering 5000 specimens, -presented by the 

 professor. He ha- also obtained, at a very moderate cost, the 

 entire collection of the late M. Gaston Genevier of Nantes, con- 

 sisting of about 7000 species from France, Spain, Algeria, 

 Asia Minor, &c., and all the typical specimens— over 500 in 

 number— of the kubi. described in his monograph of the genus 

 Rubiis. A proposal has been made by the Cambridge Philo- 

 sophical Society to make their Iari.'e and useful scientific library 

 available for scientific students generally, and to allow it to be 

 the nucleus of a much-needed library of science in the new- 

 museums, if the University will provide the salary of a hbrarian 



