And here it may not be out of place to say something concerning the survival of the beam engine. I have already referred on an earlier page to its introduction and traced its development from Newcomen’s atmospheric engine. When, in the early days of the steam engine, its use had been limited to pumping out water from mines, one connecting rod was employed in pumping and the other was driven up by the steam in the cylinder. Then, when the engine was made, not for pumping, but for giving rotatory motion, the connecting rod which had been in use for pumping was used to give a rotatory motion, by means of either the sun-and-planet movement (as in Watt’s patent) or by means of a crank (as in the patent which his workman stole from him). In America Watt’s beam engines were imitated very closely, and to-day, as every visitor to New York is aware, the curious sight is seen of enormous ferry-boats, towering high above the water, with the beam and connecting rods showing up through the top of the ship. Now this idea is all very well where the steamer is concerned only with navigation on rivers and peaceful waters, but for ocean steaming, where the deck needs to be covered in from the attacks of the mighty seas, it is out of the question. Therefore, since it was advisable to retain the beam in some form, and it could not be allowed to protrude through the deck, the obvious expedient was adopted of placing it below, but as far down in the ship as possible. As a general statement we shall not get far wrong if we state that thus placed, at the bottom, with the rods working upwards instead of downwards, it was really a case of turning the engine upside down. Thus arranged it became known as the side-lever engine, and now, if the reader will look again at the bottom illustration facing page 84, he will see our meaning. By turning the illustration round, so that the beam or side-lever is at the top, this resemblance to the old-fashioned beam engine becomes still more apparent. Later on we shall be able to show a more complicated form of the side-lever engine, but for the present this may suffice for the interest of the non-technical reader. For many years the side-lever was the recognised form of marine engine, and its advantages included that of being remarkably steady in its working because its parts were so nicely balanced. Moreover, it was easy to drive from the beam the various auxiliary parts, such as the air-pump. It was also very strong, though both heavy and costly, as it became in the course of time more complicated.