Page:Passages from the Life of a Philosopher.djvu/345

Rh made in 1839, I haye had no experience either official or professional upon the subject. My opinions, therefore, must be taken only at what they are worth, and will probably be regarded as the dreams of an amateur. I have indeed formed very decided opinions upon certain measures relative to railroads; but my hesitation to make them public arises from the circumstance, that by publishing them I may possibly delay their adoption. It may happen, as is now happening to my system of distinguishing lighthouses from each other, and of night telegraphic communication between ships at sea—that although officially communicated to all the great maritime goyemments, and even publicly exhibited for months during the Exhibition of 1851, it will be allowed to go to sleep for years, until some official person, casually hearing of it, or perhaps re-inventing it, shall have 'interest with the higher powers to get it quietly adopted as his own invention. I have given, in a former page, a list of the self-registering apparatus I employed in my own experiments.

In studying the evidence given upon the inquiries into the various lamentable accidents which have occurred upon railways, I have been much struck by the discordance of that evidence as to the speed with which the engines were travelling when they took place.

Even the best and most unbiassed judgment ought not to be trusted when mechanical evidence can be produced. The first rule I propose is, that—

Every engine should have mechanical self-registering means of recording its own velocity at every instant during the whole course of its Journey.

In my own experiments this was the first point I attended to. I took a powerful spring clock, with a chronometer movement, which every half second lifted a peculiar pen, and left