Three months later he wrote from Augsburg:
Thompson, now Count Rumford, met me by appointment at Pavia. Volta showed us his experiments on animal electricity, and said he had sent off his paper for the Royal Society about three weeks before, probably not time enough for it to be read before the vacation. I thought his experiments proved that there is no particular animal electricity, and that the animals serve only the purpose of very delicate electrometers; but they leave other circumstances unexplained.
On his return to London Sir C. Blagden wrote on November 21 to Sir Joseph Banks:
From Italy I brought two papers by Count Rumford, one on ‘Coloured Shadows,’ the other on a ‘Method of Measuring the Comparative Intensities of the Light Emitted by Luminous Bodies.’ In the former he shows neatly enough that the colours ascribed to these shadows depend entirely on comparing them with light of another colour. The method referred to in the second paper is that of the intensity of the shadows produced by the different luminous bodies. These two papers will furnish matter for nearly three meetings of the Royal Society.
Count Rumford had another serious illness in Naples in the early part of 1794. He returned to Munich in August.
He left Munich for London in 1795. He had spent the year after his return from Italy in comparative quiet. He was unfit for public business and he chiefly occupied himself by writing out the results that he had obtained. He thus made a series of essays.
In order to publish these in England and to meet his daughter, who was about to come to him from America, and to recover further his health, he obtained leave of absence from the Elector of Bavaria.
In his paper on Gunpowder in 1781 he said he would make experiments on the strength of various bodies. In 1797, when he had another paper in the ‘Philosophical Transactions’ on this subject, he added this note:
Since writing the above I have met with a misfortune which has put it out of my power to fulfil this promise. On my return to England from Germany, in October 1795, after an absence of eleven years, I was stopped in my post-chaise in St. Paul’s Churchyard, in London, at six o’clock in the evening, and robbed of a trunk which was behind my carriage, containing all my private papers and my original notes and observations on philosophical subjects. By this cruel robbery I have been deprived of the fruits of the labours of my whole life, and have lost all that I held most valuable. This most severe blow has left an impression on my mind which I feel that nothing will ever be able entirely to remove. It is the more painful to me, as it has clouded my mind with suspicions that never can be cleared up.
These essays were published at different times separately between 1796 and 1802. The two first volumes were reprinted in 1800.