REPORT OF MR. ROBERT B. LINES.
453
is called the " Sifflet. electro-automateur ” or Electro-automatic whistle, of Messrs. Lartigue & Forest. Its object is, by blowing the whistle of a coming train, to warn it of the position of a switch or optical signal which it is approaching, but which, by reason of fog, heavy snow, or even rain, or the extinction of a lamp at night, cannot be seen by the engineer. It belongs, therefore, to the class of signals between stations and trains in motion, to which I have alluded, and is a step in advance of all the apparatus just described in Group II, which give notice of danger, it is true, but whose warnings may, by reason of the distance of the switch or semaphore from the station, arrive too late.
The invention consists of two essential parts, the first being the means by which contact with the train is established, and the second the apparatus employed to sound the whistle. While in this particular instrument the two are coupled together, it is evident that the first part of the invention, if, as seems to be the case, it is uniformly successful in its operation, is capable of very wide application. I am assured by French engineers that the contact has never failed during nearly a year’s experience, with trains going at a speed of sixty miles an hour (which is very often attained by the London express), and with the ordinary obstructions of snow, dirt, and even heavy ballast, upon the track.
Plate VIII., on preceding pages, represents the apparatus which is thus described.
Fig. A shows the locomotive and the manner of making contact; B, the connections to the distant semaphore; C, the fixed contact-plate, and D, the whistle upon an enlarged scale.
The whistle is of brass, in communication with the boiler, and carried in a metallic box on its top. This box contains a lever parallel to that of the whistle, to which it is attached. This second lever is influenced by a stiff spiral spring, which tends to lower it, and consequently to let the vapor escape. It carries at its extremity, however, an armature of soft iron in contact with an electro-magnet of the ” Hughes ” pattern, composed of a permanent horseshoe magnet, the arms of 'which are prolonged by cylinders of soft iron surrounded by helices of silk-covered wire. The cylinders become the poles