550 REPORT — 1891. 



quest of the fiftli or sixth decimal is a Tery legitimate, and may become a very 

 absorbing, quest, but there are plenty of the rank and file who can undertake it if 

 properly generalled and led : not as isolated iudiyiduals, but as workers in a 

 National Laboratory under a competent head and a governing committee. By tliis 

 means work far greater in quantity, and in the long run more exact in quality, can 

 be turned out, by patient and conscientious labour without much genius, by the 

 gradual improvement of instrumental means, by the skill acquired by practice, and 

 by the steady drudgery of routine. Paris has long had one form of such an 

 institution, in the Conservatoire des Arts et Metiers, and has been able to impose tbe 

 metric system on the civilised world in consequence. It can also point to the classical 

 determinations of Regnault as the fruits of just such a system. Berlin is now . 

 starting a similar or a more ambitious scheme for a ])ermanent National Physical 

 Institute. Is it not time that England, who in physical science, I venture to think, 

 may in some sort claim a leading place, should be thinking of starting the same 

 movement ? 



The Meteorological and Magnetic Observatory at Kew (in the inauguration of 

 which this Association took so large a part) is a step ; and much useful quantitative 

 work IS done there. The new Electric Standardizing Laboratory of the Board of 

 Trade is another and, in some respects perhaps, a still closer approximation to the 

 kind of thing I advocate. But what I want to see is a much larger establishment, 

 erected on the most suitable site, limited by no specialty of aim nor by the demands 

 of the commercial world, furnished with all appropriate appliances, to be amended 

 and added to as time goes on and experience grows, and invested with all the dignity 

 and permanence of a national institution : a Physical Observatory, in fact, precisely 

 comparable to the Greenwich Observatory, and aiming at the very highest quanti- 

 tative work in all departments of physical science. That tlie arts would be benefited 

 may be assumed without proof. It is largely the necessity of engineers that has 

 inspired the amount of accuracy in electrical matters already attained. The work 

 and appliances of the mechanical engineer eclipse the present achievements of the 

 physicist in point of accuracy, and it is by the aid of the mechanician and optician 

 that precision even in astronomy has reached so high a stage. There is no reason 

 •why physical determinations should be conducted in an amateur fashion, with 

 comparatively imperfect instruments, as at present they mostly are. Discoveries 

 lie along the path of extreme accuracy, and they will turn up in the most unex- 

 j>ected way. The aberration of light would not have been discovered had not 

 Bradley been able to measure to less than 1 part in 10,000; and what a brilliant and 

 momentous discovery it was ! He was aiming at the detection of stellar parallax, 

 but the finite velocity of light was a greater discovery than any parallax. This is 

 the type of result which sometimes lurks in the fifth decimal, and which confers 

 upon it an importance beside which the demands of men who wish to serve the taste 

 and the pocket of the British public sink into insignificance. 



In a National Observatory accuracy should be the one great end : the utmost 

 accuracy in every determination that is decided on and made. Only one thing 

 should he more thought of than the fifth significant figure, and that is the sixth. 

 The consequences flowing from the results may safely be left ; such as are not 

 obvious at once will distil themselves out in time. And the great army of outside 

 physicists, assured of the good work being done at headquarters, will (to speak 

 again in astronomical parable) cease from peddling with taking transits or 

 altitudes, and will be free to discover comets, to invent the spectroscope, to watch 

 solar phenomena, to chemically analyse the stars, to devise celestial photography, 

 and to elaborate still more celestial theories ; all of which novelties may in 

 their maturity be handed over to the National Observatory, to be henceforth incor- 

 porated with, and made part of, its routine life ; leaving the advance guard and 

 skirmishers free to explore fresh territory, secure in the knowledge that what 

 they have acquired will be properly surveyed, mapped, and utilised, without further 

 attention from them. As to the practical applications, they may in any case be 

 left to take care of themselves. The instinct of humanity in this direction, and 

 the so-called solid gains associated with practical achievements, will always 

 secure a sufficient number of acute and energetic workers to turn the new territory 



