?8S 



NATURE 



(January 28, 1909 



A photograpliic method is also described which can be 

 used throughout the visible and ultra-violet regions of the 

 spectrum. 



December lo, 1908.—" Results of Magnetic Observa- 

 tions at Stations on the Coasts of the British Isles, 1907." 

 By Commander L. Chetwynd, R.N. Communicated by 

 Rear-Admiral A. M. Field, R.N., F.R.S. 



With a view to compare the values of secular change 

 of declination, horizontal force, and inclination, at various 

 stations on the coasts of the British Isles, with the values 

 derived from the continuous records at Kew Observatory, 

 observations have been made at certain stations selected 

 from those occupied by Rucker and Thorpe during their 

 magnetic survey for the epoch January i, 1891. 



The observers detailed to make the observations were 

 Captain M. H. Smyth, R.N., H.M.S. Research; Captain 

 W. Pudsey-Dawson, R.N., H.M.S. Triton; and Captain 

 J. W. Combe, R.N., H.M. surveying vessel Gladiator. 

 The stations selected were fairly distributed around the 

 coasts, so that a mean of the results would represent the 

 mean for the whole area embraced. 



The observations have been reduced to the epoch January 

 I, 1907, by means of comparisons with the records at Kew 

 Observatory. The resulting values of mean annual 

 changes for the British Isles are as follows : — 



(i) Declination 



(2) Horizontal force 



(3) Inclination 



(4) Vertical force (excepting the 



results at Dublin and 

 Tanera Mor) 



i-year period, 

 1886-1907 



- 5'7 - 

 + 197 .. 



- r-6 .. 



16-year pe-icd 

 1891-1907 



■ - 5''i 



-H87 



• - l'-4 



- 147 



The mean annual changes of declination at Kew com- 

 parable with (i) a and b are respectively s'-2 and 4'-9. 

 Thus the mean for the British Isles during the 16-year 

 period is o'-2 greater than at Kew. 



The mean horizontal force change appears to have been 

 3 7 less than at Kew. The mean inclination change 

 during the 21-year period was o'-i less, and during the 

 16-year period o'-6 less, than at Kew. 



The mean vertical force change during the 16-year 

 period has been 8 7 less than at Kew. 



Diagrams showing the mean annual changes at Kew 

 from 1889 to 1904 indicate that the declination change, 

 which since 1894 has been decreasing in amount, is now 

 increasing, and that the probable value at Kew for 

 January i, 1907, is 4'-8. For the whole of the British 

 Isles, therefore, the mean value is assumed to be 5'. 



The annual increase of horizontal force continues to 

 diminish, and is at the present time verv small ; there has 

 been a very marked diminution during the last two years, 

 and the annual increase may shortly become a decrease. 



The annual change of inclination continues to decrease 

 in amount, and is now i' (nearly). 



A comparison of the value of the mean annual change 

 of declination at Kew, Greenwich, and Stonyhurst shows 

 that durmg the period embracing Rucker and Thorpe's 

 survey (1886-94) the change at Stonyhurst was consider- 

 ably greater than at Kew and Greenwich, this being in 

 accord with the results found by Rucker and Thorpe (that 

 the secular change was greater in the north-west than at 

 Kew). 



Since the year 1894, however, the values have been in 

 closer agreement, that at Stonyhurst being slightly less 

 than at Kew. Thus it is indicated that the variations of 

 secular change are not, over the area referred to 

 synchronous. 



Comparisons of results of declination observations made 

 at sea with those made on shore show considerable differ- 

 '•If^^'j ^"'^ although the sea observations cannot be con- 

 sidered to the same degree of accuracy as the shore 

 observations, the differences are in most cases outside the 

 margin which might be assigned to this cause. 



The results indicate that the values at sea are, off the 

 east coast generally greater, and on the west coast gener- 

 a'ly less, than the corresponding values adduced from 

 ot)_serv.Tt,ons made on shore. It is intended to investigate 

 this subject further. ^ 



NO. 2048, VOL. 79] 



Royal Meteorological Society, January 20.— Annual 

 meeting.— Dr. H. R. Mill, president, "in the chair.— Presi- 

 dential address. Some aims and efforts of the society in 

 its relation to the public and to meteorological science : 

 Dr. Mill. In dealing with the subject-matter of meteor- 

 °'°?y. as of other sciences, there are two extreme 

 points of view which appeal to opposite types of 

 mind ; these are the simply observational and the purely 

 analytical, and it is one of the great advantages of 

 a scientific society to bring representatives of the two 

 types together, and to encourage mutual toleration 

 and understanding. After referring to the activity of the 

 society in the establishment of well-equipped and care- 

 fully inspected stations for accurate observations of meteor- 

 ological phenomena, and to the work carried out by various 

 special committees, the president proceeded to direct atten- 

 tion to two lines of usefulness open to the society at the 

 present time. One Is the correction of the impulsive 

 sensationalism and anti-sclentilic spirit in meteorological 

 matters of a certain section of the Press in this country, 

 which no doubt faithfully reflects the somewhat muddled 

 ideas of the careless public ; of these he gave some striking 

 Instances. The other is the advance which has been made 

 in meteorological science during -the last few years, and 

 the new opportunities it brings. He alluded to the popular 

 errors which are current concerning published weather 

 records, and the prejudicial effect of these on the meteor- 

 ological departments maintained by many municipalities. 

 He had heard of instances of reports being suppressed in 

 order to " obviate misconceptions," and of instruments 

 being moved in order to obtain more agreeable records. 

 He deprecated the keenness of rivalry between health re- 

 sorts claiming low rainfall, high sunshine, and small range 

 of temperature, and pointed out that modern bacteriology 

 had shown that dust, not rain, was the chief menace to 

 public health. He went on to say that we now stand at 

 an important point in the history of meteorology, which 

 bids fair to expand in interest and importance in the 

 twentieth century as chemistry did in the nineteenth, and 

 from the same cause, the Increasing necessity of apply- 

 ing its principles to practical ends. The point of view of 

 the meteorologist to-day Is different from that of fifty or 

 even of twenty years ago. Then the only department in 

 which much general interest could be expected was 

 climatology — the study of the average conditions of the 

 atmosphere at different places. Much remains to be done 

 in that direction : but the main interest is being diverted 

 from the study of the air 4 feet above the ground, on the 

 study of which climatology has been based, to the vast 

 expanse of the upper atmosphere miles above the abode 

 of man. He believed that in a few years the practical 

 needs of aviation will demand a far more exact knowledge 

 than_ is now required of atmospheric circulation, of the 

 relation of wind to gradient, of the disturbing influence of 

 insolation on pressure, and especially of the nature and 

 movements of cyclones and squalls, and these things br- 

 comlng of practical importance, it will become worth whi'p 

 commercially to find the means for studying them. Th» 

 position of meteorology now is not unlike that of oceano- 

 graphy before the necessity of laying cables led to the exact 

 study of ocean depths. ,nnd it is to be expected that the 

 flying machine will do for the study of the air what the 

 cables did for the study of the sea. 



Entomological Society, January 20 —Mr. C. O. Water- 

 house, president, in the chair. — Presidential address. The 

 claws of insects : C. O. Waterhouse. After briefly 

 describing the various forms of Insects' claws, which arc 

 classified as toothed, appendiculate, bifid, or pectinate, and 

 having given examples of each, the president suggested as 

 a subject for investigation, which he hoped entomologists 

 would take up as a study, " Are these forms of claw merely 

 the result of heredity without any special object, or Is 

 there evidence to show that the different forms are adapted 

 to' particular modes of life, in fact, have been developed 

 to meet special needs?" He then proceeded to show by 

 numerous examples that closely allied species often had 

 dissimilar claws, that Insects with quite different habits 

 had the same form of claw, and that others with different 

 forms of claw seemed to have the same habits. The ques- 

 tion, therefore, appeared to be still an open one requiring 

 careful investigation. 



