| Description | Tables showing deflections in electrical currents in telegraph wires at Derby and Birmingham, detected by galvanmeter at five minute intervals. Commencing at 11.40am on 7 May, and ending at 1.40pm on 8 May 1847. With some meteorological data. Columns for time of observation, left and right deflection at Derby, and at Birmingham, dry and wet bulb thermometer readings at both locations, and general weather remarks at both locations.
Data on magnetic deflections in the Midlands was used in the paper 'On the spontaneous electrical currents observed in the wires of the electric telegraph', by W.H. Barlow, Philosophical Transactions of the Royal Society, v.139 (1849), pp.61-72.
Headed [p.1]: 'Table no.1'. With some notes: 'Live wire connected with left hand Terminal of Derby Inst[rument] and with right hand terminal of Birmingham inst[rument] so that when the deflections were alike the current was passing from one treminal to the other'; and 'The firgures in red are the deflections of the Torsion deflectometer'. Endorsed [p.12]: 'Simultaneous observations at Derby & Birmingham from May 7 at noon to May 8 at noon. Table no.1'. |