but he remained aware of the activities there from his discussions with Society members, especially Morey. In addition, Robert Boyle gave him a private viewing of the Boyle/Hooke air-pump, which was used at many of the Wednesday meetings. However, Charles preferred experiments which had an immediate practical outcome and he laughed at the efforts of the Society members "to weigh air". He seemed unable to grasp the significance of the basic laws of physics being established at that time, including Boyle's Law and Hooke's Law and the concept of atmospheric pressure and the barometer and the importance of air for the support of life. Although Charles lost interest in the activities of the society, he continued to support scientific and commercial endeavours. He founded the Mathematical School at Christ's Hospital in 1673 and, two years later, following concerns over French advances in astronomy, he founded the Royal Observatory at Greenwich. He maintained an interest in chemistry and regularly visited his private laboratory. There, dissections were occasionally carried out, and observed by the king. Pepys noted in his diary that on the morning of Friday, 15 January 1669, while he was walking to Whitehall, he met the king who invited him to view his chemistry laboratory. Pepys confessed to finding what he saw there beyond him. Charles developed painful gout in later life which limited the daily walks that he took regularly when younger. His keenness was now channelled to his laboratory where he would devote himself to his experiments, for hours at a time, sometimes helped by Moray. Charles was particularly interested in alchemy, which he had first encountered many years earlier, during his exile with the Duke of Buckingham. Charles resumed his experiments with mercury and would spend whole mornings attempting to distill it. Heating mercury in an open crucible releases mercury vapour, which is toxic and may have contributed to his later ill health. Later years Charles faced a political storm over his brother James, a Catholic, being next in line to the throne. The prospect of a Catholic monarch was vehemently opposed by the 1st Earl of Shaftesbury (previously Baron Ashley and a member of the Cabal, which had fallen apart in 1673). Lord Shaftesbury's power base was strengthened when the House of Commons of 1679 introduced the Exclusion Bill, which sought to exclude the Duke of York from the line of succession. Some even sought to