i6 



NATURE 



[Septemder 8, 1 910 



wliiih bore white flowers corresponding in every respect 

 . with the ordinary chicory except in colour. Though this 

 is an uncommon occurrence, the white variety of the 

 common chicory has been recorded before. Syme in 

 English Botany " (v., p. 123) gives the colour as " pale 

 bright-blue varying to white," and Hooker, "Students' 

 Klora " (p. 210), says flowers "bright blue, rarely white." 



The summary of the weather issued by the Meteor- 

 ological Office for the summer season comprised by the 

 tiiirteen weeks from June 25 to September 3 shows that 

 the mean temperature was rather below the average 

 except in the north and west of Scotland, but the difi'er- 

 ence from the normal was nowhere large. The absolute 

 maximum temperatures ranged from 80° to 83° in all the 

 districts of the United Kingdom with the exception of the 

 north and south of Ireland and the Channel Islands, where 

 the highest temperature was in each case 79°. The 

 lowest shade temperatures ranged from 30° in the east 

 of Scotland and 34° in the north of Scotland and the 

 south-west of England to 40° in the Midland counties, 

 41° in the south of Ireland, and 47° in the Channel 

 Islands. The largest aggregate rainfall was 13-71 inches, 

 in the west of .Scotland, and the lowest 6-8i inches, in 

 the east of England. There was an excess of rain over 

 the entire kingdom e.xcept in the north of Scotland, the 

 greatest excess being 2-77 inches, in the south-west of 

 England. '1 he number of rainy days ranged from eleven 

 more tlian ilv' average in the .south of Ireland to five less 

 than the average in the north of Scotland. The largest 

 number of rainy days in any district was sixty, in the 

 south of Ireland, and the least forty-four, in the south- 

 east of England. There was a deficiency of bright sun- 

 shine for the thirteen weeks in all districts except in the 

 north of Scotland and the north of Ireland. The greatest 

 deficiency was 135 hours in the Channel Islands, 126 hours 

 in the south-east of England, and 113 hours in the north- 

 cast of England. .At Greenwich the mean temperature for 

 the three summer months this year was 1° below the 

 .-iveragp, the mean being 61°. The absolute maximum 

 l.mperature was 82.3°, which is decidedly low in com- 

 parison with former summers, and there were forty-three 

 days with a temperature of 70° or above, which is a 

 rather larger number of warm days than some recent 

 summers. The aggregate rainfall was 810 inches, which 

 is 1-32 inches more than the average, but is jess than in 

 ihe summer of either iqoS or 1909. The deficiency of 

 bright sunshine at Greenwich for the three months was 

 170 hours. 



The meteorological chart of the North Atlantic and 

 Mediterranean for September (first weekly issue, .August 18), 

 published by the Meteorological Committee, gives an 

 interesting account, with daily synoptic charts, of the 

 weather over the Atlantic for a week ending August 17, 

 and throws considerable light on the cause of the change- 

 able weather over the British Islands during that period. 

 Between August 11 and 14 a barometric depression passed 

 slowly from about 55° N., 30° \V., to the neighbourhood 

 of our western coasts, causing showery weather generally 

 over western Europe, and thunderstorms in many parts 

 of the United Kingdom on the night of August 14. During 

 the latter half of the period another depression developed 

 over eastern Canada, and furnished a good example of 

 such disturbances crossing the whole of the North Atlantic. 

 It arrived off the west of Scotland by the morning of 

 August 17 ; changeable weather therefore again set in, 

 and south and south-west winds became strong on parts 

 of our western and southern coasts. 

 NO. 2132, VOL. 84] 



Tmk director-general of Indian observatories has issued 

 a memorandum, dated August 6, on the monsoon con- 

 ditions prevailing during June and July, with anticipations 

 for .August and .September. The combined distribution of 

 rainfall in June and July was rather irregular, being con- 

 siderably in e.xcess in some provinces and in defect in 

 others. In July the monsoon conditions were weak over 

 a large area, and an almost complete break in the rains 

 occurred in the second and third weeks. From informa- 

 tion obtained as to the conditions over a large part of 

 the earth's surface since the date of the memorandum of 

 June 9 (see N.^TURE, July 28), the director -general con- 

 cludes, !H(cr a\ia^ that the general outlook appears more 

 uncertain than usual, but there is no reason for expecting 

 a large defect in the total amount of rainfall during 

 .August and September. 



The Annuar'to of the Rio de Janeiro Observatory, 

 1909-10, contains, in addition to ephemerides and astro- 

 nomical data for the two years stated, a large number of 

 tables relating to the physics of the globe. The tables 

 usually employed in the reduction of astronomical and 

 meteorological observations, and the values of the various 

 units are very complete and handy for reference. The 

 compilation extends to 405 octavo pages, but contains no 

 original scientific discussions. 



l.e Radium for July devotes seven pages to tables of 

 constants of ionisation and of radio-activity compiled by 

 I'lof. T. H. Laby. The following constants are tabu- 

 lated : — Rates of re-combination of ions, their mobilities, 

 the electric charges they carry, the quotients of the charges 

 by the masses, path and velocity of a rays, number of 

 o particles emitted by radium, heat developed by radio- 

 active substances, and a number of other radio-active and 

 atomic constants which may be calculated from these. In 

 the same number M. W. Duane, of Madame Curie's 

 laboratory, gives a description of an arrangement for regis- 

 tering photographically the number of a particles emitted 

 by a radio-active substance, founded, like the counting 

 method of Prof. Rutherford and Dr. Geiger, on the 

 augmentation of the ionisation of a rarefied gas within a 

 closed vessel by the collision of the o particles with the 

 molecules. The vessel, of small capacity, is of ebonite, 

 closed below by a brass plate having a small window in 

 it covered with a thin sheet of mica. The radio-active 

 substance is placed below the window, and the brass plate 

 is raised to an electrical potential nearly sufficient to cause 

 a discharge to take place between it and a wire electrode 

 at the top of the vessel, which is connected to a gold-leaf 

 electroscope. .An image of the gold leaf is formed on a 

 photographic film moving behind a slit. The gold leaf is 

 bi ought back to the normal position after each displace- 

 ment by means of a leal; produced by polonium outside the 

 electroscope. Several reproductions of photographs ob- 

 tained are given, which show the displacements produced 

 by the a particles, but the author gives a further photo- 

 graph showing displacements obtained without a particles, 

 the explanation of which he is not yet in a position to give. 



The current number of the Zeiischrift fiir physikalische 

 Chemie contains another contribution from the van 't Hoff 

 Laboratory at Utrecht on the allotropy of the elements, 

 the alleged allotropy of lead having been examined by 

 E. Cohen and Is. Inouye. During the electrolysis of solu- 

 tions of lead salts, it was shown by O. Lehmann that two 

 kinds of crystals can be formed according to the condi- 

 tions, one crystallising in the regular and the other in the 

 monosymmetric system. It has now been found that 

 cells set up with these different crystals show no difference 



