Experimental equipment to test electrical conductivity in a vacuum mb-height 4477 Showing Roger and Anne Hillet

Showing Roger and Anne Hillet kneeling in prayer

The Queen (centre) seen here with Princess Margaret

left arm around the chair back

showing the men at work

Sir George Grey

Experimental equipment to test electrical conductivity in a vacuum mb-height 4477 Showing Roger and Anne HilletPlate 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