him ; one has to bring a good deal of intelligence to that task oneself.” At the age of forty, if he had come to know the world, our friend would exclaim : “Tacitus is one of the greatest writers that ever lived.”
There is a certain kind of book, extremely numerous in Germany, which do not, indeed, scare us from reading them, or send us off to sleep immediately, or stupefy us, but which after about an hour’s time reduce the mind to a certain condition of lassitude, very similar to the feeling which we get shortly before a thunderstorm. If we lay the book aside, we are not in the mood to study anything ; if we begin to write, we write in just the same style ourselves; even if we at once begin to read the best books they seem to acquire a tepid tastelessness. I know from personal experience that against this sad condition there is no specific like a cup of coffee and a pipe.
The constant familiarity which K . . . I had with books of all sorts and conditions, the titles which he read and heard mentioned, produced in his head a species of universal encyclopaedia, and to have seen it all printed would not have been unworthy of the greatest “observation collector.” As I frequently conversed with him about mathematical books, I know him rather more intimately in that connection. His ideas were formed somewhat after this fashion :—He noticed the reputation of Kastner, and his income—first conclusion: mathematics is a possible way both to fame and bread. He noticed that mathematical books employ a language different from
