When the _Aberdeen_ was completed, 2,000 tons of dead-weight were put on board, and the consumption was tested on a four hours’ run at 1,800 horse-power. The result was the consumption at the rate of 1.28-lbs. per indicated horse-power per hour, with Penrikyber Welsh coal. From this the designer of the engine inferred a sea consumption of good Welsh coal at the rate of 1·5 to 1·6-lbs. per indicated horse-power. The maximum measured mile speed was 13·74 knots, with 2,631 indicated horse-power, and a consumption of 1 ton 17 cwt. per hour. The vessel started from Plymouth on 1st April, 1881, upon her first voyage to Melbourne, with 4000 tons of coals and cargo—weight and measurement—on board. She arrived at Cape Town on the 23rd April, having accomplished the distance—5,890 miles—in 22 days. After taking in about 140 tons of coal, she left for Melbourne on the 24th, and arrived there on the 14th May, in 20 days. The whole time occupied in steaming from Plymouth to Melbourne was, therefore, 42 days. Her average indicated horse-power on the voyage has been about 1,880, and the consumption less than thirty-four tons per day, or at the rate of about 1·69-lbs. per indicated horse-power over the whole voyage. Since these results were obtained, Messrs Napier have fitted three sets of 5000 H.P. triple expansion engines into vessels built for the Compania Transatlantica Mexicana, and are completing a duplicate of the _Aberdeen_. The firm of Messrs Denny & Coy., Dumbarton, are at present making engines of the triple expansion type for the new steamers of the Shaw, Savill & Albion Company’s direct New Zealand service. There are four cylinders and two cranks, the cylinders being arranged in pairs, tandem fashion, the small on the top of the large. Expansion takes place in three stages, the first small cylinder taking steam from the boilers about five-eights of the stroke, and expanding into the valve chest of the second small cylinder, where it is further expanded. From thence it exhausts into the valve chest common to both the large cylinders described. The steam to be supplied to these engines is to have a pressure of 160-lbs. per square inch, the highest yet carried in marine engines. These instances of actual advancement, taken in conjunction with the favourable light in which the triple expansion principle is regarded by our foremost marine engineers, augur well for the future of steamship propulsion. * * * * *