In order to find the most economical method of lighting his Workhouse at Munich, he devised a new way of measuring the relative quantities of lights by their shadows. His arbitrary standard was a London made Argand lamp. He first experimented on the resistance of air to light, then on the loss of light in its passage through different kinds of glass, and in its reflection from a plate glass mirror, then on the relative quantities of oil burnt by different lamps and relative quantities of light emitted by different substances, and lastly on the transparency of flame. He made these experiments into a paper on the ‘Relative Intensities of the Light Emitted by Luminous Bodies,’ and it was read before the Royal Society, February 6, 1794; and on February 20 another paper was read, being an ‘Account of some Experiments on Coloured Shadows,’ and he came to the conclusion that our eyes are not always to be believed, even with respect to the presence or absence of colours. For his national and scientific work he received various honours between 1783 and 1794. In 1785 he was elected member of the Bavarian Academy of Sciences, which had been established in 1758, and he was made chamberlain to the Elector. In 1786 the King of Poland, at the request of the Elector of Bavaria, conferred on him the Order of St. Stanislaus. This was done because the statutes of Bavaria did not allow a foreigner to receive any national honours. In 1787, when in Prussia, he was made a member of the Berlin Academy of Sciences. In 1788 the Elector made him Major-General of Cavalry and Privy Councillor of State, and he was placed at the head of the war department. On May 29, 1789, he was elected a foreign honorary member of the American Academy of Arts and Sciences, and he was made Lieutenant-General of the Bavarian Armies and received the command of a regiment of artillery. In 1791, in the interval between the death of the Emperor Joseph and the coronation of Leopold II., the Elector of Bavaria was one of the Vicars of the Empire, and he made Sir Benjamin Thompson a Count of the Holy Roman Empire, and gave him the Order of the White Eagle. Early in the following year the wife of Count Rumford, who had been a great invalid, and who had lived with her son by her first husband and with her daughter, the child of Rumford, died at the age of 52. Her own property had given her every comfort that her ill health required. At the end of this year Count Rumford was in correspondence with his early friend Colonel Baldwin, through whom probably for some time previously he had sent money to his mother. He wrote to Colonel Baldwin from Munich, January 18, 1793: You could hardly conceive the heartfelt satisfaction it would give me to pay a visit to my native country. Should I be kindly received? Are the remains of party spirit and political persecutions done away? Would it be necessary to ask leave of the State?