4 REPORT — 1882. 



ample shadow its cultivators will find it both profitable and pleasant to 

 meet, at least once a year; and considering that this tree is not the 

 growth of one country only, but spreads both its roots and branches 

 far and wide, it appears desirable that at these yearly gatherings other 

 nations should be more fully represented than has hitherto been the case. 

 The subjects discussed at our meetings are without exception of general 

 interest, but many of them bear an international character, such as the 

 systematic collection of magnetic, astronomical, meteorological, and 

 geodetical observations, the formation of a universal code for signalling 

 at sea, and for distinguishing lighthouses, and especially the settle- 

 ment of scientific nomenclatures and units of measurement, regarding all 

 of which an international accord is a matter of the utmost practical im- 

 portance. 



As regards the measures of length and weight it is to be regretted 

 that this country still stands aloof from the movement initiated in France 

 towards the close of last century ; but, considering that in scientific 

 work metrical measure is now almost universally adopted, and that its 

 use has been already legalised in this country, I venture to hope that 

 its universal adoption for commercial purposes will soon follow as a 

 matter of course. The practical advantages of such a measure to the 

 trade of this country would, I am convinced, bo very great, for English 

 goods, such as machinery or metal rolled to current sections, are now 

 almost excluded from the continental market, owing to the unit measure 

 employed in their production. The principal impediment to the adoption 

 of the metre consists in the strange anomaly that although it is legal 

 to use that measure in commerce, and although a copy of the standard 

 metre is kept in the Standards' Department of the Board of Trade, it 

 is impossible to procure legalised rods representing it, and to use a non- 

 legalised copy of a standard in commerce is deemed fraudulent. Would 

 it not be desirable that the British Association should endeavour to brino- 

 about the use in this country of the metre and kilogramme, and, as a 

 preliminai-y stop, ask the Government to be represented on the Inter- 

 national Metrical Commission, whoso admirable establishment at Sevreg 

 possesses, independently of its practical work, considerable scientific in- 

 terest, as a well-found laboratory for developing methods of precise 

 measurement ? 



Next in importance to accurate measures of length, weight, and time, 

 stand, for the purposes of modern science, those of electricity. 



The remarkably clear lines separating conductors from non-con- 

 ductors of electricity, and magnetic from non-magnetic substances, enable 

 us to measure electrical quantities and efi'ects with almost mathematical 

 precision ; and, although the ultimate nature of this, the youngest 

 scientifically investigated form of energy, is yet wrapt in mystery, its 

 laws are the most clearly established, and its measuring instruments 

 (galvanometers, electrometers, and magnetometers) are amongst the. 



