The Royal Institution possesses a book which no lover of science can regard with other than reverential interest. It is a small, well-bound quarto of some 386 manuscript pages, of notes taken by Michael Faraday, when a bookbinder’s apprentice, of the last of Davy’s lectures at the Institution. A Mr. Dance--his name deserves to be held in remembrance--had given the youth a ticket for the lectures, and Faraday, perched in the gallery over the clock, had zealously followed the expositions of the brilliant lecturer, and had subsequently, when asking for an engagement at the Institution, sent in these notes, neatly written out and embellished with drawings of the apparatus, to the Professor as evidence of the applicant’s “knowledge, diligence and order.” Among the lectures is one on chlorine, given on March 14th, 1812, the notes of which are as characteristic of the auditor as of the lecturer. We read:-- “Accustomed for years to consider the chemical principles of the French School of Physical Sciences as correct, I had adopted them and put faith in them until they became prejudices, and I even felt unwilling to give them up when my judgment was fully convinced by experiment that they were erroneous. I know that this is the case in some degree with almost every person; he is unwilling to believe that he is wrong and therefore feels averse to adopt what is right when it opposes his principles.” Then follows an account of various experiments showing the properties of chlorine, and the proofs that it contains no oxygen:-- “Oxygen does combine with chlorine. I have ventured to name the compound _euchlorine_; it is of a very bright yellow-green colour. Names should represent things not opinions for in the last case they often tend to misrepresent and mislead. “Had Mr. Berthollet obtained oxygen from chlorine there would have been no error in his theory, but by not attending to the minute circumstances of his experiment, by not ascertaining that the water present acted no part and was not decomposed he fell into an error, and of course all the conclusions he drew were false and erroneous. Nothing should be allowed but what can be proved by experiment, and nothing should be taken for granted upon analogy or supposition.” Faraday concludes as follows:--