Report of the Kew Observatory Committee. It 



Electric Tramways. — During the year a variety of schemes have been 

 promoted for applying electric traction on the trolley system to tram 

 lines in the neighbourhood of the Observatory, and one of these schemes, 

 promoted by the London United Tramway Company, for a new line 

 between Kew Bridge and Hounslow, passing within 1,300 yards of 

 the Observatory, has received the sanction of Parliament. The Com- 

 mittee, roused by the fate that has befallen the magnetic observa- 

 tories at Toronto and Washington, requested Professor Riicker and 

 Professor Perry to take the matter in hand. A series of experi- 

 ments made at various places in London and Leeds, under the 

 general supervision of Professor Riicker, showed that electric rail- 

 ways and tramways, satisfying presumably all the existing require- 

 ments of the Board of Trade, produced very sensible disturbances in 

 a declinometer at distances of two or three miles. This fact was 

 brought before the notice of the Royal Society, who in turn entered 

 into communication with the Board of Trade, with the result that 

 the following clauses were inserted in the London United Tramway 

 Company's Bill : — 



1. The whole circuit used for the carrying of the current; to and 

 from the carriages in use on the railway shall consist of conductors, 

 which are insulated along the whole of their length to the satisfaction 

 in all respects of the Commissioners of Her Majesty's Works and 

 Public Buildings (in this section called the " Commissioners "), and 

 the said insulated conductors which convey the current to or from 

 any of such carriages shall not at any place be separated from 

 each other by a distance exceeding one-hundredth part of the 

 distance of either of the conductors at that place from Kew Obser- 

 vatory. 



2. If, in the opinion of the Commissioners, there are at any time 

 reasonable grounds for assuming that, by reason of the insulation or 

 conductivity having ceased to be satisfactory, a sensible magnetic 

 field has been produced at the Observatory, the Commissioners shall 

 have the right of testing the insulation and conductivity upon giving 

 notice to the Company, who shall afford all necessary facilities to the 

 engineer or officers of the Commissioners, or other person appointed 

 by them for the purpose, and the Company shall forthwith take all 

 such steps, as shall in the opinion of the Commissioners be required 

 for preventing the production of such field. 



3. The Company shall furnish to the Commissioners all necessary 

 particulars of the method of insulation proposed to be adopted, 

 and of the distances between the conductors which carry the current 

 to and from the carriages. 



It is understood that the above clauses will be insisted on by the 

 Board of Trade in the case of any other tram line which can be 

 shown to be a probable source of danger to the Observatory. 



