224 



NA TURE 



[August 19, IC09 



on tlie Continent and in England, excepting that the 

 minimum temperatures are somewhat lower there than 

 on this side of the Atlantic. This is probably on ac- 

 count of the lower latitude. The gradients for the 

 various seasons are given, but the distribution of the 

 ascents is not wide enough to make these figures of 

 much value. Thus the value of the upper part of the 

 gradient for the spring is obtained from ascents on 

 sixteen consecutive days in the spring of 1906, and we 

 have no ground for assuming that these sixteen days 

 represent the average spring conditions. 



There is also a discussion of the results obtained 

 from the kite ascents at Blue Hill. The values of the 

 pressure, of the departures from the normal of the 

 temperature, of the humidity, and of the direction 

 and strength of the wind at different heights are 

 plotted for the various segments of cyclones and anti- 

 cvclones, and the curves and tables are well worth 

 careful study. 



(2) In addition to the ordinary observations and to 

 those made by means of kites during the year, there 

 is a general summary for the period igoi-5, and a 

 table of mean temperature for the twenty years 1886- 

 1905. -Although the great difference of climate on the 

 eastern and western sides of the Atlantic is well 

 known, one cannot help feeling surprise on being re- 

 minded bv a publication of this sort how' great the 

 difference is. Thus at Blue Hill, in latitude 

 42° 12' 44" N., a latitude further south than any part 

 of France, and, be it remarked, closer to the Gulf 

 Stream than many parts of England are to the 

 Atlantic, we find that, on the average, the ponds are 

 covered with ice from the end of November to the 

 end of March, while in England, 10° further north, 

 few people under twenty-five vears are able to skate, 

 owing to the almost total absence of opportunity during 

 recent vears. The difference is, of course, due to the 

 prevailing westerly winds, which bring the temperature 

 of the .Atlantic to western Europe and the continental 

 temperature of North .\merica to the Atlantic coast of 

 Canada and the United States. 



There is also a very interesting account of the 

 meteorology of total solar eclipses by Mr. H. Helm 

 Clayton. In the brief space of a review it is not 

 possible to refer to this in detail, but the tables give 

 a collection of the changes that have been observed 

 on various occasions. The temperature effect is per- 

 fectlv plain, and is shown to vary with the intensity 

 of the natural solar radiation at the time and place. 

 It is pointed out how ditTicult it is with the other 

 elements to separate the changes due to the eclipse 

 from the casual and diurnal changes that are going 

 on at the same time, but it appears to be proved that 

 the barometer and hvgrometer are influenced. 



The shadow bands of the eclipse are discussed by 

 Prof. Rotch, who comes to the conclusion that they 

 are produced bv rays from the narrow crescent of light 

 passing through strata of different refractive index, 

 the motion being due to the wind. 



AVGVST METEORIC SHOWER. 



ON .August 10 the sky was watched for ij hours, 

 but only 19 meteors were noticed, of which 12 

 were Perseids. The shower seemed disappointingly 

 feeble. 



On .August II it became evident that the display 

 had greatly intensified. In 2J hours before midnight 

 yt, meteors were counted, and they were nearly all 

 Perseids from 46°-H58°. Very few- large ones were 

 seen ; in fact, the meteors were generally small, and 

 the display could not be regarded as a very con- 

 spicuous one. The sky became rather foggy towards 



NO. 2077, VOL. 81] 



midnight, and nianv small meteors must have been 

 hidden. The vapour increased, and next morning 

 .after sunrise there was a thick autumn-like fog, which 

 was not dispersed until the sun had risen high. 



On .August 12 the atmosphere was beautifully clear 

 when night came in, but meteors appeared to be 

 scarcely so numerous as on preceding night. They 

 were, however, of astonishing brilliancy, and made 

 the shower a very attractive and notable one. In 

 all 65 meteors were counted between gh. and 

 I2h. 52m., but clouds partially veiled the sky 

 after iih. and obscured many which would other- 

 wise have been seen. Relatively to the total 

 number counted, I have never, within a long 

 experience, remarked such an abundance of fine, 

 flashing' meteors. Their long, graceful flights and 

 highlv luminous trails added to the interesting and 

 striking nature of the spectacle. A fireball at g.42 

 gave a lightning-like flash, and must have presented 

 its best effect to observers at London and in the 

 eastern counties. The following were the recorded 

 paths of a few of the most brilliant objects : — 



These were all Perseids, and duplicate observations 

 would be valuable as furnishing data for the computa- 

 tion of the real paths. The very clear summer 

 weather has recently ofl'ered an almost unique oppor- 

 tunity for studying the progress of the shower during 

 its approach to the maximum. 



The finest meteor which appeared during the 

 display was recorded on .August 12 at gh. 42ni. It 

 lit up the sky like a flash of lightning, and left :i 

 streak which remained visible for several minutes. 

 The fireball was observed at Bristol by the writer, and 

 also by the follow-ing : — Observers at Greenwich ; Dr. 

 W. J. S. Lockyer, London; Howard E. Goodson, 

 .S. Kensington; H. Wilkie, Bognor ; R. Langton Cole, 

 Havant; J. S. Sowerby, Tatsfield, Surrey; T. K. 

 Jenkins, Blama ; George Powell, Aberdare. The 

 meteor w^as a magnificent specimen of the Perseids, 

 and w-as quite noteworthy, even during a shower 

 which consisted of unusually brilliant members. Its 

 radiant point was at about 47° + 58°, and it passed over 

 the earth from above a point ten miles \V. of Ips- 

 wich to a point about 15 miles E. of Croydon. Its 

 height was from 87 to 53 miles, length of path 68 

 miles, and velocity about 35 miles per second. The 

 observations from Havling Island, Bristol, and S. 

 Kensington are in excellent agreement. The streak 

 was generated in the latter portion of the flight. As 

 viewed from Bristol, the nucleus brightened several 

 times, and just where the outbursts had occurred the 

 streak exhibited sections which were intensely lumin- 

 ous. From Hayling Island this streak lay 4 degrees 

 under ct and 5 Cassiopeia, and during the short interval 

 it remained in sight it assumed a serpentine form 

 and drifted two or three degrees to the westwards. 



The following are particulars of four brilliant 

 meteors recentlv seen and estimated =21: — 



