426 



SCIENCE. 



[N. S. Vol. II. No. 4a. 



Standard gauges, consisting of hollow 

 cylinders with plugs to fit, but differing in 

 diameter by the y^'j^ or the Tt?C(j(j of an 

 inch, were given to his workmen, with 

 the result that a degree of accuracy incon- 

 ceivable to the ordinary mind became the 

 rule of the shop. 



To render the construction of accurate 

 gauges possible, "Whitworth devised his 

 measuring machine, in which the move- 

 ment was affected by a screw ; by this 

 means the distance between two true 

 planes might be measured to the one-mil- 

 lionth of an inch. 



These advances in precision of measure- 

 ment have enabled the degree of accuracy 

 which was formerly limited to the mathe- 

 matical instrument maker to become the 

 common property of every machine shop. 

 And not only is the latest form of steam 

 engine, In the accuracy of its workman- 

 ship, little behind the chronometer of the 

 early part of the century, but the accu- 

 racy in the construction of experimental 

 apparatus which has thus been introduced 

 has rendered possible recent advances in 

 many lines of research. 



Lord Kevlin said, in his Presidential Ad- 

 dress at Edinburgh, "Nearly all the grand- 

 est discoveries of science have been but the 

 rewards of accurate measurement and pa- 

 tient, long-continued labor in the sifting 

 of numerical results." The discovery of 

 argon, for which Lord Eayleigh and Prof. 

 Ramsay have been awarded the Hodgkin 

 prize by the Smithsonian Institution, affords 

 a pregnant illustration of the truth of this 

 remark. Indeed, the provision of accurate 

 standards not only of length, but of weight, 

 capacitj', temperature, force and energy, are 

 amongst the foundations of scientific inves- 

 tigation. 



In 1842 the British Association obtained 

 the opportunity of extending its usefulness 

 in this direction. In that year the Govern- 

 ment gave up the Koyal Observatory at Kew 



and offered it to the Eoyal Society, who de- 

 clined it. But the British Association ac- 

 cepted the charge. Their first object was- 

 to continue Sabine's valuable observations 

 upon the vibrations of a pendulum in 

 various gases, and to promote pendulum 

 observations in different parts of the world. 

 They subsequently extended it into an 

 observatory for comparing and verifying 

 the various instruments which recent dis- 

 coveries in physical science had suggested 

 for continuous meteorological and magnetic 

 observations, for observations and experi- 

 ments on atmospheric electricitj', and for 

 the study of solar physics. 



This new departure afforded a means for 

 ascertaining the advantages and disadvan- 

 tages of the several varieties of scientific in- 

 struments, as well as for standardizing and 

 testing instruments, not only for instru- 

 ment makers, but especiallj^ for observers 

 by whom simultaneous observations were 

 then being carried on in different parts of 

 the world, and also for training observers 

 proceeding abroad on scientific expeditions. 

 Its special object was to gromote original 

 research, and expenditure was not to be 

 incurred on appai-atus merely intended to 

 exhibit the necessary consequences of 

 known laws. 



The rapid strides in electrical science had 

 attracted attention to the measurement of 

 electi'ical resistances, and in 1859 the Brit- 

 ish Association appointed a special com- 

 mittee to devise a standard. The standard 

 of resistance proposed by that committee 

 became the generally accepted standard, un- 

 til the requirements of that advancing sci- 

 ence led to the adoption of an international 

 standard. 



In 1866 the Meteorological Department 

 of the Board of Trade entered into close 

 relations with the Kew Observatory, and 

 in 1871 Mr. Gassiot transferred £10,000 

 upon trust to the Eoyal Society for the 

 maintenance of the Kew Observatory, 



