After having done its work, the water is discharged into the return mains, being thus used over and over again. The experience obtained in the working of the _Quetta_ shows that a donkey boiler of the usual size, just sufficient for steam winches, enables the cargo to be discharged in half the time: in other words, does double the work on a given coal consumpt with compound surface-condensing pumping engine, and the hydraulic system. The advantages of hydraulic machinery have been thus summarised:—A pair of engines in one place do, with no noise and half the consumption of fuel, the work usually performed by perhaps a dozen donkey engines, while about £30 or £40 a voyage is saved in wear and tear. The increase of speed obtained in loading and discharging cargo practically ensures a quicker voyage. The rapidly working machinery necessitates double gangs of men in the hold; but though the hands are more numerous they are paid for a shorter time, and the cost of labour per ton of cargo is thus less than usual. The prime outlay is considerably greater than under the ordinary system, but it is calculated that in at least three years the extra expense will have been saved. Notwithstanding the considerable increase in cost (more than double that of steam equipment) of the hydraulic system, the British India Association have seen their way to fit the succeeding steamers they have built, similarly to the _Quetta_, namely, the _Bulimba_, _Waroonga_, and _Manora_, the two intervening ships having their emigrant quarters ventilated by fans driven by hydraulic engines, as well as the usual deck equipment. In addition to the above, there have already been nine other steamers fitted successfully by Mr Brown’s firm with hydraulic machinery—including the Union Steamship Coy.’s _Tartar_, of 4340 tons—and there is every prospect now of its taking the place of the noisy steam machinery in at least our most important passenger lines. * * * * *