New Standard Weights and Measures 121 



of the Royal Society had considered a proposal of this kind 

 fifteen years ago, but had been deterred from acting on it 

 by the serious practical difficulties which then presented 

 themselves. 



The familiar fact that the barometer falls before rain 

 and rises after it was then discussed, and the intention 

 expressed, which, however, was not fulfilled, of resuming 

 the subject at the next meeting. 



Dr. Carpenter stated that the bars of the Menai Bridge, 1 

 after having been some time in place, had been found to 

 have become highly magnetic and also brittle. Mr. Grove 

 thought that the former effect was probably due to their 

 vertical position and constant agitation, in lines approxi- 

 mately parallel to those of terrestrial magnetism. He 

 did not regard the brittleness as a necessary consequence of 

 the magnetism, though it also was probably a result of the 

 continual vibratory disturbance. It had been shown by 

 experiment that the elasticity of metals was affected by 

 electric action and magnetization. 



1853. At the 58th meeting (June i8th) Dr. Miller 2 

 gave some account of the standard instruments, lately 

 prepared at Kew ; weights had been made from i pound 

 avoirdupois to o-oi of a grain. For the heavier from 100 

 to 7000 grains gun-metal, thickly electro-gilt, had been 

 used, and platinum for those less than 100 grains. A 

 standard yard had been laid down upon a flat-rolled brass 

 scale between gold pins. These standards had been used 

 in constructing, for meteorological purposes, two barometer 

 tubes of one inch internal diameter. He added some 

 details of the operation of boiling the mercury in these 

 unusually large tubes. 



1 The Suspension Bridge, opened in 1825, must be meant, though the 

 Britannia Tubular Bridge was completed in 1850. 



" This must have been Prof. W. A. Miller, for in the course of his remarks 

 he mentioned Prof. W. H. Miller, of Cambridge, who was an active member 

 of the committee, appointed in 1843 to reconstruct the standards of weight 

 and rr-easurement destroyed by the burning of the Houses of Parliament 

 in 1834. The work was completed by 1854, when the standards of weight, 

 length, and capacity were authorized (18 and 19 Viet. ch. 72). 



