at Friedrichsdorf; but I do not know that any particularly intimate relation existed between them. Dr. Poppe, director of the Gewerbeschule (Trade School), now deceased, on whose advice he chiefly relied, was then one of his more intimate friends, Professor Oppel being occasionally consulted about more intricate mathematical problems. Of the ‘meteorological recorder’ invented by Reis I recollect but its existence, but nothing at all of a ‘fall-machine’ of his construction. The velocipede I only recollect, because he lent it to me for a masquerade. At his suggestion we altered it into a large musical-box, putting Herr Peter inside, who played on the clarinet when I turned a handle. Dr. Kellner states that its chief merit consisted in being able to go downhill, and that poor Reis came back (uphill) puffing away, dragging his velocipede behind him. Kellner no doubt could give valuable information on Reis’s theory of electricity, his conviction that there was only one kind of electricity, his acoustic researches, and those on radiation of electricity, his galvanoplastic experiments, &c., &c. “In personal appearance Reis was not very refined, but he had a striking countenance and a very powerful look. Though occasionally very irritable, especially with dunces, he was always warm-hearted, and showed great kindness to those who cared to understand him. Reis’s views of the telephone may, of course, have changed after I knew him, and looking at his later instruments, one of which I possess, I cannot help thinking they did; at any rate, I do not see how, in these instruments, the current got interrupted at all, and the instruments must have acted like microphones, whether known or unknown to him. When listening to the instrument he frequently said to me, “You understand it is a ‘molekular Bewegung’ (molecular motion). “I am sorry that, owing to the lapse of time, I am unable to throw more light on Reis’s original labours in a field of physical science which promised so much for the future; but insufficient as are my recollections, they may not be without public interest, and at any rate I am glad of this opportunity of offering my humble tribute of regard and affection to the memory of my old teacher and friend. “Yours truly, “Rudolph Messel.” * * * * * Heinrich Hold. [Herr Hold, formerly a colleague of Philipp Reis in the Garnier Institute at Friedrichsdorf, but now proprietor of a leather factory in the same place, was teacher of mathematics. He was in his younger days a fellow-student of Professor Tyndall at Halle, and was well acquainted with physical science in general. His intimate connection with Reis, and close knowledge of Reis’s work, enable him to confirm the testimony of others in many important points.] To Professor S. P. Thompson in Bristol. “Esteemed Sir,