158 



NATURE 



[June i6, 1892 



of the fifty years, 1841-1890. The highest air temperature 

 in the shade was 85°*i on July 17, and the lowest i2°o on 

 January 10. The mean monthly temperature in 1891 

 was below the average in all months excepting June, 

 September, October, December. In January it was 

 below the average by 4""4, in April and August by 3''o, 

 and in May by 2°"8. 



The mean daily motion of the air in 1891 was 278 

 miles, being 4 miles below the average of the preceding 

 twenty-four years. The greatest daily motion was 960 

 miles on December 10, and the least 34 miles on February 

 23 and 24. The greatest pressure registered was 315 

 lbs. on the square foot on November 11. On December 

 10 the pressure plate was not in action. 



The number of hours of bright sunshine recorded 

 during 1891 by the Campbell-Stokes sunshine instrument 

 was 1222, which is about 66 hours below the average 

 of the preceding fourteen years, after making allowance 

 for difference of the indications with the Campbell and 

 Campbell- Stokes instruments respectively. The aggre- 

 gate number of hours during which the sun was above 

 the horizon was 4454, so that the mean proportion of sun- 

 shine for the year was 0*274, constant sunshine being 

 represented by i. 



The rainfall in 1891 was 25*0 inches, being 0-5 inches 

 above the average of the preceding fifty years. 



Chronometers, Time Signals, and Longitude Opera- 

 tions. — The number of chronometers and deck watches 

 now being tested at the Observatory is 157 (91 box 

 chronometers, 19 pocket chronometers, and 47 deck 

 watches). The annual competitive trial of chronometers 

 commences on July 2, and the trial of deck watches on 

 October 22. 



In the year ending 1891 May 10, the average daily 

 number of chronometers and deck watches being regularly 

 rated was 243, the total number received was 765, the 

 total issued 750, and the number set to repair 442. 



At the annual trial of chronometers the performance 

 was good, the average trial number of the first six was 

 2 r4, which compares favourably with those of previous 

 years. 



The dropping of the time-balls is next referred to. 

 The Greenwich one was not raised on October 14, Dec- 

 ember 10 and 13, 1891, owing to the violence of the 

 wind ; on April i, 1892, the springs of the mean solar 

 clock failed to act, and on October 19 and November 22 

 failure in the connections was the cause. 



The return signal from Deal was interrupted last 

 November several times, owing to an accumulation of 

 grease which had been applied to the piston. Signals 

 from Devonport clock failed on 51 days, and those from 

 the Westminster clock on 14 days. 



The pubHcation of the observations for the Paris- 

 Greenwich longitude in 1888, and of those for the Dun- 

 kerque-Greenwich longitude in 1889, has been delayed 

 pending a redetermination of the former longitude which 

 was commenced on June 6 of the present year ; and 

 it is hoped to settle several questions of importance 

 raised by the discussion of the results obtained in 1888. 



The first stage of the operations for the longitudes 

 Montreal-Canso-Waterville-Greenwich was completed on 

 May 23. The time of transmission along the cable 

 Waterville-Canso was about a quarter of a second — a 

 result confirmed by a rough comparison of signals on 

 1892 May II. Prof McLeod, of Montreal, paid a similar 

 preliminary visit to Canso in 1891 June, and found an 

 accordant value for the time of transmission. Four 

 portable transits were used for the time determinations. 

 These latter were made in all on 14 nights at Greenwich, 

 1 2 at Waterville, and about the same number at Canso 

 and Montreal. The preliminary reduction gives every 

 promise of satisfactory accuracy at Greenwich and 

 Waterville. 



Captain Grant, R.E., has been at work at the Observa- 



NO. I 181, VOL. 46] 



tory practising the requisite transit observations for 

 determining the boundary of Mashonaland. 



In the Astronomer- Royal's general remarks at the con- 

 clusion of his report, he refers to a plan he has devised 

 for making observations out of the meridian with a transit- 

 circle. He proposes to have it so constructed that by 

 means of a turn-table it can be placed and firmly fixed in 

 certain definite azimuthal, the instrument " being used 

 essentially as a transit-circle for a complete series of ob- 

 servations in the selected azimuths plane." This instru- 

 ment, as he says, would advantageously replace the 

 existing altazimuth, and could be used "not only for the 

 important object of making extra-meridian observations 

 of the moon but also for observations of the sun, planets, 

 and stars (in the meridian as well as out of the meridian), 

 for the elimination, as far as practicable, of systematic 

 errors, and for the more accurate determination of as- 

 tronomical constants." The aperture of the instrument 

 he suggests should be 8 inches, with circles of 3 feet 

 diameter, read by four microscopes, and he thinks that a 

 suitable position for it could be found about 90 feet north 

 of the declination magnet, where " an unobstructed view 

 could be secured by mounting it with its axis at a height 

 of about 20 feet above the ground." 



NOTES. 



The Ladies' Soiree of the Royal Society is being held this 

 evening as Nature goes to press. 



The annual meeting of the American Association for the 

 Advancement of Science will be held at Rochester, N.Y,, from 

 August 18 to 24. 



The late Dr. W. J. Walker placed at the disposal of the 

 Boston Society of Natural History a grand honorary prize " for 

 such investigation or discovery as may seem to deserve it, pro- 

 vided such investigation or discovery shall have been made 

 known or published in the United States at least one year pre- 

 vious to the time of award." This prize has been unanimously 

 awarded to Prof. James D. Dana. In recognition of the value 

 of Prof. Dana's scientific work, and in testimony of the Society's 

 high appreciation of his services to science, the maximum sum 

 of one thousand dollars has been awarded. 



In the new number of the Journal of the Marine Biological 

 Association Mr. Ernest W. L. Holt gives an interesting account 

 of the work he has lately done in connection with his North 

 Sea investigations. The objects of these investigations, as ex- 

 plained in the report of Mr. Calderwood, the Director of the 

 Plymouth Laboratory, are : — (i) to prepare a history of the 

 North Sea trawling grounds, comparing the present condition 

 with the condition say twenty or thirty years ago, when com- 

 paratively few boats were at work ; (2) to continue, verify, 

 and extend operations as to the average sizes at which the 

 various food-fishes become sexually mature ; (3) to collect 

 statistics as to the sizes of all the fish captured in the vicinity of 

 the Dogger Banks and the region lying to the eastward, so that 

 the number of immature fish annually captured may be esti- 

 mated ; (4) to make experiments with beam trawl nets of 

 various meshes, with a view to determine the relation, if any, 

 between size of mesh and size of fish taken. It is obvious that 

 a considerable time must elapse before trustworthy data can be 

 collected on all these points by one inquirer. Mr. Calderwood 

 therefore notes that in Mr. Holt's early reports it has been 

 thought advisable not to treat each heading in detail, since one 

 season of the year may be more suitable for collecting informa- 

 tion on one point than on another, but rather simply to state 

 the results of work accomplished. During the spawning season 

 most attention must necessarily be given to heading No. 2, so 

 that in Mr. Holt's present report the relation of size to imma- 

 turity is principally mentioned. Work of a similar nature done 

 by Mr. Holt himself in Ireland, by Dr. Fulton in Scotland, 



