_Answer._ The instrument just described is the latest form of self-regulating injector, manufactured by Messrs. Wm. Sellers & Co., and is called by its makers the INJECTOR OF 1876. It is started and stopped by a simple movement of the lever _H_. This lever _H_ moves a cross-head _I_, on the guide-rod _J_; it also, by means of stops _T_ and _Q_, on rod _L_, opens and closes the starting-valve _K_. In fig. 70 the instrument is shown shut off, and with the starting-valve _K_ open. On the rod _B_ are two valves, a small one _W_ and a larger one _X_. A stop or collar is shown a short distance beyond the large valve _X_. If the lever _H_ be drawn back until this collar comes in contact with the valve _K_, it will have raised the valve _W_ from its seat, and steam will escape through a small passage in the centre of the conical regulating plug. The steam so admitted is sufficient to lift the water, which will then be driven through _D_, and past the valve _K_, and escape at _P_. Drawing back the lever _H_ to the end of its stroke, after the water has been lifted, the large valve _X_ is raised, and the lug on the lever _H_, coming in contact with the stop _T_, on the rod _L_, the valve _K_ is closed. The jet is fully established and the water is driven into the boiler. At the entire end of stroke of the lever _H_, the latch _V_ falls into notches on the rod _J_, when, as the lever is moved forward toward the position shown in fig. 70, this latch will click over the notches and hold the lever in any desired position between the maximum and minimum delivery. QUESTION 140. _What attachments are needed besides the instrument to render it effective?_ _Answer._ A globe-valve should be placed in the steam pipe leading to the injector, to be closed only when there is occasion to remove the injector when steam is up, and in cold weather, to prevent the condensation of steam in the pipes at the end of its trips. During all the working time of the injector, this valve should be wide open. QUESTION 141. _In what position, and in what location on the engine should the injector be placed?_ _Answer._ On the right hand side, high enough up to have an air chamber below the injector, above the top of the water in the tank when the latter is full. QUESTION 142. _What is required to keep the instrument in working order?_