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214 deck on the port side. The steering gear consists of a 514 in. by 5% in. steam engine situ- ated on the upper deck engine casing, the customary lead of chains, spring buffers, quadrant, etc., have been fitted. The gear is also arranged to operate by hand. A steel derrick post with steel der- rick is fitted on the port. side of the main deck and arranged in such a way that it can readily handle the buckets when these have to be changed. It is also arranged to serve the hatch over a workshop which has been fitted on the lower deck for- ward. The accommodation for the dredg- ing master and officers is fitted on the promenade deck aft, and have been designed to give as much light -and air as -possible.. The crew 'are accommodated with large rooms on inside the THE MARINE REVIEW the lower deck forward. These ves- sels usually work day and night throughout the season of navigation, and therefore accommodation for a double crew has been provided. Suit- able galley, pantry, storeroom and lavatory accommodation has been in- stalled. The forepeak has been arranged for water ballast, and a reserve feed tank has been fitted immediately aft of this for use if ever the vessel goes to salt water. Fresh water tanks are incorporated with the ship's structure just forward of the coal bunkers. Complete arrangements for pumping and draining, heating and ventilating, have been installed, and a complete equipment of telegraphs, nautical instruments, river and dredging lights, etc., has been supplied, together with a full supply of spare parts for all the machinery and dredging gear. June, 1914 Both ships were practically com- pleted last autumn, but could not be got away before the close of naviga- tion owing to the poor delivery of important materials, and had, there- fore, to be held until the opening of navigation this year. The first. vessel successfully carried out digging and speed trials on April 23 and 24 under the supervision of Mr. McNab, of the department of Marine and Fisheries; Mr. Forneret, the chief engineer of the St. Lawrence ship channel, and Mr. Steadworthy, dredge master; the h. p. p. developed being 950 at 120 revolutions per min. and steam at 180 Ibs. per square inch, which is well over the specified requirements. The second vessel's trials were equally successful, and were completed May 6. Both vessels will leave Colling- wood for Sorel, P. Q., a distance of over 1,000 miles on May 9th. Superheated Steam HE reintroduction of superheat- I ers in boilers, and the use of su- perheated steam im engines of the mercantile marine, has been brought about by continuous research together with costly experiments by the greater knowledge obtained in the process of making and amalgamating metals, by the improvements in the manufacture of such metals into tubes and other suitable forms, by the introduction of oxy-acetylene and electric welding, by the preparation of lubricating oils for use under high temperatures, together with a mass of data, the result of years of experimenting and investigation, and which has now been put to the crucial test of practical working. Superheaters, when introduced into marine boilers some 70 years ago, de- veloped rapid deterioration, producing such a heavy bill for repairs and re- newals that they were regarded as too costly, not to say dangerous, for use on board a steamer, and it is possible ~ that the experiences and the 'troubles which then developed have contributed to the extreme caution exhibited by many engineers and steamship owners in considering the pros and cons of the 'use of superheaters and superheated steam today. *Paper read before the Institute of. Naval Architects, April 2, 1914, -ton to Rio de Janeiro and back'. The Use of Superheaters and Super- heated Steam in Mercantile Steamers* In the Mechanics' Magazine of April, 1861, appears an article on "Superheated Steam", which is a most interesting record of what may be considered the last serious effort to give a superheat to steam for use in steamers, and the fol- lowing extracts are taken therefrom: "Thomas Howard is credited with es- tablishing the fact that great economy might be effected by the principles of superheating in about the year 1833, and that Dr. Haycroft shortly after- wards urged its application on the ground that it would effect a saving of 30 per cent in fuel. The Prince Alfred, of 200 horsepower, belonging to the Inter-Colonial Royal Mail Co., is stated as being 'the first sea-going vessel work- ing with unmixed superheated steam, and fitted with Partridge's system', Other vessels mentioned are the Da- masmus, of 200 h.p., the consumption - per indicated horsepower being reduced to 3lbs. Inthe Tyne a vessel of 400h. p. was fitted, and 'it was found very bene- ficial during a voyage from Southamp- The H.M.S. Dee was fitted, and after four years was reported as in good condi- tion. Altogether 50 vessels were fitted with 'Partridge's' apparatus, represent- ing 10,000 to 12,000 h. p., and the sav- ings effected by the use varied from 15 to 30 per cent. In general, the steam By Harry Gray was superheated to about 340 deg., and the pressure ranged from 10 lbs. to 25 Ibs. per sq. in. | Other superheating ap- paratus mentioned are those of Parsons and Pilgrims, fitted on the Osprey in 1859, also H.M.S. tug Bustler in 1859, and in 15 other vessels. :Lamb's super- heater, patented in 1858, was adapted to over 50 vessels with a saving of 20 to 40 per cent. Boden and Clarke's superheaters were fitted on the South- ampton in 1860, trading between South- ampton and Channel Islands, of 262 h. p. condensing engines with two-slide oscilating 60-in. cylinders, 5-ft. stroke. She burnt only 37 tons on each trip out and in, averaging 22 hours, or about 12 Ibs. per horsepower. The Despatch was also fitted. Butler's superheater was fitted to the City of Nantes, with a saving of 30 per cent and increased speed. Pullen, Cresswell and Long- staff's apparatus, patented in 1860, and many others which showed equally fa- vorable results. Reference is also made to the researches of Dr. Taylor, Mr. Brande, Professor Faraday, Mr. Fair- 'bain and others." J. and W. Dudgeon, of Millwall, be- tween 1859 and 1870, fitted about 40 vessels with Beardmore's system of superheat. The steam engine being essentially a heat engine, no excuse is needed for