Z1^ 



NATURE 



\AMgust 15, 1889 



We append a list of the Sections : — (i) Mathematics and 

 Astronomy; (2) Physics; (3) Chemistry; (4) Botany; (5) 

 Zoology ; (6) Entomology ; (7) Mineralogy and Geology ; (8) 

 Ethnology and Anthropology ; (9) Anatomy ; (10) Physiology ; 

 (ii) General Pathology and Pathological Anatomy ; (12) Phar- 

 macology ; (13) Pharmacy and Pharmacognosis ; (14) Medicine ; 

 (15) Surgery; (16) Gynaecology; (17) Children's Diseases; (18) 

 Neurology and Pyschiatry ; (19) Diseases of the Eye; (20) 

 Diseases of the Ear; (21) Laryngology and Rhinology ; (22) 

 Dermatology and Syphilis ; (23) Hygiene ; (24) Medical Juris- 

 prudence ; (25) Medical Geography ; (26) Military Sanitation ; 

 (27) Dentistry; (28) Veterinary Medicine; (29) Agricultural 

 Chemistry ; (30) Mathciratics and the Natural Sciences in 

 Relation to Education ; (31) Geography ; (32) Philosophical 

 Instruments. 



THE PROGRESS OF SCIENCE AS EXEMPLI- 

 FIED IN THE ART OF WEIGHING AND 

 MEASURING} 



''PWO centuries ago the world was just beginning to awaken 

 from an intellectual lethargy which had las'ed a thousand 

 years. During all that time the children had lived as their 

 parents before them, the mechanical arts had been at a stand- 

 still, and the dicta of Aristotle had been the highest authority 

 in science. But now the night of mediasvalism was approaching 

 its end, and the dawn of modern progress was at hand. Galileo 

 had laid the foundation for accurate clocks by discovering the 

 isochronism of the simple pendulum ; had proved that under the 

 action of gravity light bodies fall as rapidly as heavy ones ; had 

 invented the telescope, and with it discovered the spots on the 

 sun, the mountains on the moon, the satellites of Jupiter, and 

 the so-called triple character of Saturn ; and, after rendering 

 himself immortal by his advocacy of the Copernican system, had 

 gone to his grave aged, blind, and full of sorrows. His con- 

 temporary, Kepler, had discovered the laws which, while history 

 endures, will associate his name with the theory of planetary 

 motion, and he also had passed away. The first Cassini was 

 still a young man, his son was a little child, and his grandson 

 and great-grandson, all of whom were destined to be directors 

 of the Paris Observatory, were yet unborn. The illustrious 

 Huyghens, the discoverer of Saturn's rings and the father of the 

 undulatory theory of light, was in the zenith of his powers. The 

 ingenious Hooke was a little younger ; and Newton, towering 

 above them all, had recently invented fluxions, and on April 28, 

 1686, had presented his "Principia" to the Royal Society of 

 London, and given the theory of gravitation to the world. 

 Bradley, who discovered nutation and the aberration of light ; 

 Franklin, the statesman and philosopher, who first drew the 

 lightning from the clouds ; Dollond, the inventor of the achro- 

 matic telescope ; Euler, the mathematician who was destined to 

 accomplish so much in perfecting algebra, the calculus, and the 

 lunar theory ; Laplace, the author of the "Mecanique Celeste" ; 

 Rumford, who laid the foundation of the mechanical theory of 

 heat ; Dalton, the author of the atomic theory, upon which all 

 chemistry rests ; and Bessel, the greatest of modern astronomers 

 — these and others almost as illustrious, whom we cannot even 

 name tonight, were still in the womb of time. 



Pure science first felt the effects of the new intellectual life, 

 and it was more than a century later before the arts yielded to 

 its influence. Then came Hargreaves, the inventor of the 

 spinning-jenny ; Arkwright, the inventor of the cotton-spinning 

 frame; Watt, who gave us the condensing steam-engine; 

 Jacquard, the inventor of the loom for weaving figured stuffs ; 

 Murdock, the originator of gas lighting ; Evans, the inventor of 

 the high-pressure steam-engine ; Fulton, the father of steam 

 navigation ; Trevithick, who ranks very near Watt and Evans 

 in perfecting the steam-engine ; and Stephenson, the father of 

 railroads. If now we add the names of those who have given us 

 the telegraph, to wit : Gauss, the eminent physicist and the 

 greatest mathematician of the present century ; Weber, Wheat- 

 stone, and Henry— all famous physicists — and Mor-e, the 

 inventor and engineer ; we have before us the demi gods who 

 have transformed the ancient into the modern world, given us 

 machinery which has multiplied the productive power of the 

 human race many-fold, annihilated time and space, and bestowed 



' Annual Address of Dr. William Hardness, President of the Ph'losophical 

 Society of Washington, delivered on December 10, 1887. 



upon toiling millions a degree of comfort and luxury which was 

 unknown to kings and emperors of old. 



The discoveries and inventions of the last two centuries have 

 so far exceeded all others within historic times that we are amply 

 justified in calling this an age of phenomenal progress, and 

 under the circumstances a little self-glorification is pardonable — 

 perhaps even natural. The weekly and monthly records of 

 scientific events which appear in so many newspapers and 

 magazines are the immediate result of this, and the great 

 increase of ephemeral scientific literature has led multitudes of 

 educated people to believe that such records represent actual 

 progress. The multiplication of bricks facilitates the building 

 of houses, but does not necessarily improve architecture. Simi- 

 larly, the multiplication of minor investigations improves our 

 knowledge of details, but rarely affects the great philosophic 

 theories upon which science is founded. The importance of 

 human actions is measured by the degree in which they affect 

 human thought, and the only way of permanently affecting 

 scientific thought is by modifying or extending scientific theories. 

 The men who do that are neither numerous nor do they require 

 weekly paragraphs to record their deeds ; but their names are 

 honoured by posterity. Even in this golden age the advance of 

 science is not steady, but is made by spasmodic leaps and 

 bounds. Mere scientific brick-making, commonly called pro- 

 gress, is always the order of the day until some genius startles 

 the world by a discovery affecting accepted theories. Then every 

 effort is directed in the new line of thought until it is measurably 

 worked out, and after that brick-making again resumes its place. 

 While the progress in two centuries has been immense, the pro- 

 gress in a week or a month is usually almost nil. Optimism has 

 its uses in many departments of human affairs, but science should 

 be cool and dispassionate, having regard only for the truth. To 

 make a trustworthy estimate of the actual state of the whole vast 

 realm of science would be a task beyond the powers of any one 

 man ; but perhaps it will not be amiss to spend the time at our 

 disposal this evening in briefly reviewing the recent progress and 

 present condition of the fundamental processes upon which the 

 exact sciences rest — I allude to the methods of weighing and 

 measuring. 



Physical science deals with many quantities, but they are all 

 so related to each other that almost every one of them can be 

 expressed in terms of three fundamental units. As several 

 systems of such units are possible, it is important to select the 

 most convenient, and the considerations which guide us in that 

 respect are the following : — 



(i) The quantities selected should admit of very accurate 

 comparison with other quantities of the same kind. 



(2) Such comparisons should be possible at all times, and in 

 all places. 



(3) The processes necessary for making sucli comparisons 

 should be easy and direct. 



(4) The fundamental units should be such as to admit of easy 

 definitions and simple dimensions for the various derived units. 



Scientific men have long agreed that these requirements are 

 best fulfilled by adopting as the fundamental units a definite 

 length, a definite mass, and a definite interval of time. Length 

 is an element which can be very accurately measured and copied, 

 but it must be defined by reference to some concrete material 

 standard, as, for example, a bar of metal ; and as all substances 

 expand and contract with changes of temperature, it is necessary 

 to state the temperature at which the standard is correct. A 

 standard of mass, consisting of a piece of platinum, quartz, or 

 other material not easily affected by atmospheric influences, 

 probably fulfils the conditions set forth above better than any 

 other kind of magnitude. Its comparison with other bodies of 

 approximately equal mass is effected by weighing, and as that is 

 among the most exact of all laboratory operations, very accurate 

 copies of the standard can be made, and they can be carried 

 from place to place with little risk of injury. Time is also an 

 element which can be measured with extreme precision. The 

 immediate instruments of measurement are clocks and chrono- 

 meters, but their running is checked by astronomical observa- 

 tions, and the ultimate standard is the "rotation of the earth 

 itself. 



It is important to note that the use of three fundamental units 

 is simply a matter of convenience and not a theoretical necessity, 

 for the unit of mass might be defined as that which at unit dis- 

 tance would generate in a material point unit velocity in unit 

 time ; and thus we should have a perfectly general system of 

 measurement based upon only two fundamental units — narneh 



namel5^ 



m 



