lO 



NATURE 



[September 2, 1915 



effects of varying temperature on the rate of 

 pocket watches. 



The main fact to be noticed in connection with 

 these early trials is that they settled the lines 

 on which future tests have been made. The 

 qualities demanded now are, as they were then, 

 smallness of daily rate, uniformity of rate in 

 different positions of the balance, and constant 

 rate within a considerable range of temperature. 

 The number of variables is small, and wherever 

 chronometer testing is carried on, little change has 

 been made in the manner of conducting the test. 

 Details vary at different observatories, but one 

 general practice is pursued. For a certain number 

 of days constituting "a period," the watch is 

 kept in a vertical position with pendent up, or 

 to the right, or left, and horizontally, with dial 

 up or down. Further the watch is submitted to 

 varying temperature, generally covering about 

 50° F. in the whole, and throughout the several 

 "periods" the daily rate is determined by com- 

 parison with a clock regulated to Greenwich Mean 

 Time. The relative excellence of the instrument 

 tested in shown by assigning marks for its per- 

 formance in each period, and herein there is room 

 for the exercise of individual judgment in deciding 

 relative merit. One authority may consider the 

 elimination of temperature effects of more import- 

 ance than smallness of rate, and give higher marks 

 accordingly. To secure accurate adjustment for 

 " positions " may seem to some the most desirable 

 qualification. 



M. Gautier hints that steps might be taken with 

 advantage to secure greater uniformity among 

 different observatories. But the system of award- 

 ing marks is of no great importance, for a good 

 watch comes so near perfection that it will take 

 nearly the maximum of marks, however they are 

 divided. M. Gautier remarks that a comparison 

 between the trials at Kew and Geneva shows that 

 the results are in close agreement, and that this 

 conclusion is warranted is proved by the fact that 

 the best watch at Geneva, tested by the Kew 

 system of marks, would have 95'9, while the best 

 at Kew was assigned 96*1 marks. 



At Geneva, to within the last few years, the total 

 number of marks that could be earned was 300, 

 of which 100 were assigned to steadiness of daily 

 rate (m) ; 100 to uniformity of rate in different 

 positions (/>) ; 70 for excellence of temperature 

 compensation (c) ; and 30 for smallness of varia- 

 tion (y) throughout the test. At the same time 

 limiting values are assigned to m, p, c, and r, 

 which may not be exceeded without loss of cer- 

 tificate. These several maximum values are 

 shown in the expression from which is computed 

 the number of marks to which the watch is 

 entitled. 

 N = (o»75-w/) 40o/3+{2»-50-/) 40+(o»-2o-f)35o+(5»-oo-r)6. 



If any one of these terms is negative the watch 

 fails to meet the test, but it can be withdrawn, 

 corrected by the maker, and re-submitted to test in 

 those particulars in which it failed, but the oppor- 

 tunity of competing for the highest places in com- 

 petitive tests is denied to such watches. Later, 

 NO. 2392, VOL. 96] 



the number of marks was increased to, 1000, but 

 the two scales are not directly comparable, for the 

 conditions of test have been made more severe. 

 The variation from daily rate must not exceed 

 o'5 sec. in any one test, the rate in different 

 positions is reduced from 2*5 sec. to z'o sec, and 

 in other respects the demand for greater accuracy 

 is on the same scale. 



It is gratifying to know that the improvement 

 in manufacture has more than kept pace with 

 the requirements for test, and that M. Gautier 

 is able to report that the highest excellence yet 

 attained was exhibited by the chronometers of 

 1914. This also is the experience of Kew, where 

 of sixty-two watches submitted to trial, forty-eight 

 were awarded more than 90 per cent, of the maxi- 

 mum marks. Of even greater significance is the 

 increasing certainty of manufacture. The writer of 

 this article has long held that after a certain high 

 standard has been reached, the maker must de- 

 pend upon some lucky accident for pre-eminence. 

 He is unable to explain the cause of superiority, 

 and though he may take equal care he cannot 

 repeat his success. But when we find that the 

 Kew record is held by M. P. Ditisheim, of Chaux- 

 de-Fonds, with a score of 96'!, and the same 

 maker is able to secure the first four places in a 

 competition of unusual severity, it is evident that 

 chance is fast being eliminated. Such improved 

 workmanship demonstrates the success that has 

 attended the scheme of annual competition, 

 originated with the view of encouraging the Swiss 

 watch manufacture. The number of watches sub- 

 mitted for test is not large, about 200 per annum, 

 but a healthy competition has raised a high 

 standard of excellence, and taught the public what 

 to expect. 



Besangon leads the way in France. The method 

 of test varies slightly from that of Geneva, but 

 the details only concern the expert. The point wc 

 would make is that such establishments are 

 eminently useful and instructive. By advertising 

 widely what has been accomplished they make the 

 public dissatisfied with inferior workmanship, and 

 they offer opportunities for the careful maker to 

 gain recognition for his work. A standard of 

 accuracy is set up that encourages the public dis- 

 tribution of time signals, and promotes a smoother 

 working of national life. 



FREDERICK MAN SON BAILEY, C.M.G. 



THE death of Frederick Manson Bailey, 

 C.M.G., the veteran Colonial Botanist of 

 Queensland, which was announced in the last 

 issue of Nature, will be felt as a great loss to 

 Australian botany. He inherited his botanical 

 tastes from his father, John Bailey, who emigrated 

 to South Australia in 1838, the family having con- 

 ducted the business of nurserymen and seedsmen 

 In London for many years. F. M. Bailey helped 

 his father for a time in the nursery business at 

 Adelaide, which he established on resigning the 

 position of Government botanist — to which post 

 he was appointed on his arrival in South Aus- 



