Experimental equipment to test electrical conductivity in a vacuum mb-height 4477 Formal photographic portrait of Thomas

Formal photographic portrait of Thomas Lauder Brunton

South elevation of the old St Paul's Cathedral

Sir George Grey

The Queen (centre) seen here with Princess Margaret

Experimental equipment to test electrical conductivity in a vacuum mb-height 4477 Formal photographic portrait of ThomasPlate 9 figures 1 2 from the paper 'Electrical experiments made in order to ascertain the non conducting power of a perfect vacuum', by William Morgan, Philosophical Transactions of the Royal Society, vol. 75 (1785), pp. 272 278. Figure 1 shows a 15 inch mercury gauge partially coated with tin foil, emptied of air and inverted into a mercury cistern. A wire is visible within this reservoir, through which an electrical current was passed but without