66 



NATURE 



\Nov. 25, 1875 



conceding this view with regard to all the other causes of 

 movement, Mr. Darwin finds a difficulty in accepting it 

 as regards movement caused by curvature from a touch, 

 or what is ordinarily called sensitiveness. On this point 

 he remarks that the movement of Revolving Nutation 

 (Sachs's term for " the continuous self-bowing of a whole 

 shoot successively to all points of the compass ") differs 

 from that due to touch, in so far that in some cases the 

 two powers are acquired by the same tendril at different 

 periods of growth ; and the sensitive part of the tendril 

 does not seem capable of nutation. A more important 

 cause of hesitation is the extraordinary rapidity of the 

 movement. Mr. Darwin has seen the extremity of a 

 tendril of Passifiora gracilis, after being touched, dis'- 

 tinctly bend in twenty-five seconds, and often in thirty 

 seconds ; and he doubts whether it is possible to believe 

 in such rapidity of growth as would account for such 

 movement. In reference to this we may simply remark 

 that instances are on record of extraordinarily rapid 

 groA'th — as in the case of the flower-stalk of Vallismria 

 to the extent of half an inch in an hour or more — even 

 without any abnormal irritation. 



The student will find in Mr. Darwin's work a resume oi 

 everything known to the present date on this interesting 

 and curious department of Vegetable Physiology. 



OUR BOOK SHELF 



Report of the Meteorological Reporter of the Government 

 of Bengal for 18747 a7id Administration Report of the 

 Meteorological Reporter to the Government of Bengal 

 for 1874-75. By W. G. Willson, Officiating Meteo- 

 rological Reporter. (Calcutta : Bengal Secretarial 

 Press, 1875.) 



This Report, drawn up by Mr. W. G. Willson, who 

 has acted as officiating reporter during the absence of 

 Mr. Blanford, keeps up the high character of the pre- 

 vious reports of this Office It contains not merely the 

 dry details which form an integrant part of such reports, 

 but also an able discussion of them both in their prac- 

 tical and theoretical bearings. As regards new obser- 

 vations, the most important are those from Sibsagar, 

 situated in the north-east of the Assam Valley. The 

 large barometric oscillation from 10 A.M. to 4 P.M., which 

 on the average of the twelve months of 1874 amounted to 

 o'i33 inch, will indicate their high strictly meteorological 

 value. The hourly observations of the different instru* 

 ments made on four days of each month at a number of 

 the stations are a valuable piece of work, and the dis- 

 cussion of the results three or four years hence will be 

 looked forward to with much interest by meteorologists. 

 An admirable feature of these reports are the averages, 

 corrected up to date in all instances, which are given 

 with the discussion of each meteorological element, thus 

 affording the means of an immediate comparison of the 

 monthly results with the best averages that can possibly 

 be had. Of these averages and comparisons we would 

 direct special attention to those of the rainfall, which is 

 of so great importance in Indian meteorology. Rainfall 

 averages for different perioJs were prepared during the 

 past year for the information of the Government of India, 

 These have since been further amplified and corrected, 

 and the present report gives the average monthly and 

 annual rainfall for 146 stations, and incomplete averages 

 for some months for other twenty-three stations. An 

 example of the practical application of the rainfall dis- 

 cussions of the Office is given in the report. A forecast 

 of the rainfall was called for by the Government from the 

 Office in the latter part of July 1874, when considerable 



apprehensions were entertained regarding the prospects 

 of the principal rice-crop of the year. A comparison of 

 the peculiarities of the rainfall up to the end of July with 

 those of past years, and the general similarity of the 

 meteorological circumstances with those of 1872, induced 

 Mr. Willson to submit the opinion that the rainfall in the 

 latter months of the monsoon would turn out as favour- 

 able as in 1872, a forecast which fortunately was fully 

 reaUsed. 



The inter-relations of the pressure, temperature, winds, 

 and rainfall are particularly inquired into, and some of 

 the results are of very high importance, of which those 

 referring to the weather of January, April, May, and 

 June may be specially referred to. From a careful exa- 

 mination of the observations, Mr. Willson infers that 

 during the hot weather months there is an upper westerly 

 current from the heated plains of Northern India blowing 

 towards the cooler regions of Assam above the southerly 

 winds of the delta ; and that, if this be so, the vapour 

 carried from the Bay of Bengal by the southerly winds in 

 the hot weather months is mostly diffused upwards and 

 thence transferred by the upper westerly current to 

 Assam, where it descends, and, meeting the cold north- 

 easterly surface winds, its vapour is precipitated in the 

 copious rains which fall in Assam in this season. Ac- 

 cording to this view, the excessive rainfall of Assam in 

 May 1874 is completely accounted for by the very 

 unusual strength of the southerly sea winds over the 

 delta in that month ; by the abnormally low surface- 

 pressure and high temperature over the plains of Northern 

 India, and by the relatively high surface-pressure and low 

 temperature over Assam. It will be seen that there is 

 here indicated a further development of the important 

 practical question of the prediction of the character of 

 the coming season. As regards these and many other 

 questions of meteorology, still more important obser- 

 vations and discussions may be looked for from the 

 reports of the new Meteorological Department now being 

 organised by Mr. Blanford for the whole of India, in- 

 cluding British Burmah and the islands of the Bay. 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return^ 

 or to correspond with the writers of, rejected manuscripts. 

 No notice is taken of anonymous communications.^ 



Oceanic Circulation 



I HAVE, at Prof. Thorpe's suggestion (vol. xii. p. 514), com- 

 pared the results obtained by the use of Prof. Hubbard's Table of 

 the expansion ofsea-vvater with that obtained from Muncke's, and 

 find them almost identical. Both give 2 feet 6 inches as the amount 

 by which the expansion of Column B * (lat. 23° N.) exceeds that 

 of the Equatorial Column. Muncke's Table gives 3 feet 6 inches 

 as the amount by which Column A (lat. 38° N.) exceeds that of 

 the equatorial, while, according to Prof. Hubbard's Table, it is 

 3 feet 4 inches, being a diflTerence of only 2 inches. 



Dr. Carpenter objects + to my result on the ground that I 

 have omitted the consideration of the inferior salinity of the 

 equatorial column. Had I taken this into account, ha thinks I 

 would have found that it makes a difference in the opposite 

 direction of about I foot in 1,026, which would more than neu- 

 tralise the whole 35 feet of slope derived from temperature. I 

 do not know upon what grounds he believes that the differ- 

 ence in salinity is so great between the equatorial and Atlantic 

 columns. Certainly the researches of the Challenger Expeditiin 

 do not warrant any such conclusion. It is true that there is an 

 excess of salinity in the surface-water of the North Atlantic, but \ 

 it does rot extend to any great depth. This sup2rior salinity of 

 the warm upper stratum of the North Atlantic, it may be ob.served, 

 is an additional evidence that the water is of Gulf-stream origin. 



* Columns A. B, and C refer to Dr. Carpenter's section as given in my 

 paper on the "Crucial Test" argument, read before the British Association 

 at Bristol, and published in full in xhe. Philosophical Magazine for September. 

 A refers to North Atlantic column in lat. 38°, B to column in lat. ^f, and 

 C to equatorial column. 



t See Nature, vol xii. p. 533. 



