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oe THE MARINE REVIEW February, 1912 Auxiliary and Engineering Specialties The Porhydrometer Among the auxiliaries exhibited at the annual meeting of the Lake Car- riers' Association at Detroit, none attracted as much attention as the porhydrometer. The display con- sisted of a model of a ship floating in a tank with the porhydrometer in- stalled.. This instrument was describ- ed in the September, 1909, Marine Re- virw and is the invention of an Itali- an engineer. Everybody who inspect- ed the model was much impressed with its simplicity and scientific ac- | curacy. The porhydrometer is sim- ply an adaptation of the laws of nature governing displacement and water level. It is really an indication of the vessel's own displacement and - virtually turns the ship into a weigh- ing machine. It consists of a small steelyard attached to an aerometer or float which measures accurately any alteration in the displacement due to weight, placed or removed from aboard. The aerometer is suspended -- inside an iron pipe placed in the center of the vessel into which the sea water has free access and rises to a.level corresponding to the draught of the ship. The pipe extends well below the light water line to -well above the load line. The aerometer having exactly proportionate horizon- tal areas at the various immersions to the areas of the planes of flotation at the present draughts or immersion of the vessel, has an exactly similar dis- placement and thereby reduces the enormous weights dealt with to a measurable quantity. The trim of the- vessel, whether lying on an even keel or not, does not affect the accuracy of the porhydrometer. It weighs with unfailing accuracy anything put aboard, whether forward or aft. The whole apparatus does not occupy much space and its weight, all told, will vary from 200 to 600 pounds. The sole agents for the device in the United States are the McNab Co., Bridgeport, Conn. Schuette Recording Compass The 'recording compass manufac- tured by the Schuette Recording Compass 'Co., Manitowoc, Wis., is daily receiving additional endorse- ment. The recording compass is at- tracting a great deal of attention abroad and has been ordered by a number of leading steamship lines. A ' McNab number of vessel owners who saw the compass at the exhibition of auxili- aries in conjunction with the Lake Carriers' meeting. at Detroit were much impressed with it and orders for the compass will undoubtedly be placed by them. It is an infallible record of what occurs in the wheel- house during the 24 hours of the day. McNab Engine Indicators Alexander McNab, the inventor of the McNab direction and revolution indicators which have met with so much success in this country, attend- ed the annual meeting of the Lake Carriers' Association. The McNab in- dicator is avery simple little device which indicates whether the engine is going ahead or astern and in such a manner that there is no possibility of a mistake. Mr. McNab has re- ceived a number of testimonials re- garding his indicator. In fact, a num- ber of the leading lake fleets have adopted it and it is extensively used also on the coast. Mr. McNab has extended his com- pany to include a number of nautical. and engineering appliances, and_ has changed the name of the company from the McNab Indicator Co. to the 'Co., with headquarters at Bridgeport, Conn. The specialties in- clude the porhydrometer and Dow- nie's dead-lip valve. The Eckliff Automatic Circulator The Eckliff Automatic Circulator Co., of Detroit, had a very attractive display at the meeting of the Lake Carriers' Association, in Detroit, show- ing a model of their circulator in- stalled on a model boiler. The little model certainly attended to business all the time and was watched with interest by a great many engineers. This circulator was described in the October, 1911, Marine Review, and its purpose is to equalize the tempera- ature in the bottom and top of the boiler and thereby eliminate' the trouble caused by leaky, circumferen- tial seams and the pitting and crack- ing of furnace bottoms. It is expected that the circulator will be installed on a number of lake freighters before the season of 1912, Nautical Library One of the most enterprising ex- hibitions at the Lake Carriers' meet- ing was the nautical library compiled by Burrows Bros. Co., of Cleveland. Evidently it was got up on the spur of the moment because a number of standard works were missing from the display, but it was nevertheless a step in the right direction. The leading vessel interests as a rule are quite willing to furnish the men aboard ship anything in the way of literature that they may deem helpful to them in their business. The larger class of carriers have very excellent libraries. Marine Searchlights Lake masters are practically a unit in maintaining that lake vessels should be equipped. with searchlights. What is needed is a more powerful light than the simple little hand- light that is carried on several of them, as it is quite important at times that stakes and other unlighted aids to navigation be picked up promptly. The Carlisle & Finch Co., Cincinnati, O., are just sending out. a catalog illustrating their searchlight projectors. Their marine projectors are of great power, being equipped with glass lens mirrors, the curvature of which concentrates the light from the arc so that it emerges from the lamp in a-_ practically straight ray. A focusing screw and hand-wheel are provided for varying the spread of the light. The weight of the projectors. 1s carried on a train of steel balls so that the lamp may be. turned in either direction with the greatest ease. The ef- fective range of the 9-in. projector is said to be from % to 3% miles, the 14-in. projector from 1 to 1% miles, the 24-in. projector 3 miles and the 38-in. projector 5 miles. Meno Message Case An interesting little booklet en- titled "Lost Ships" was distributed by the Meno Message Case Co., De- troit, Mich., at the meeting of the Lake Carriers' Association. This lit- tle booklet gives a list of the mys- terious total losses of the great lakes. It is known that there have been many such, notably the Western Re- serve, Gilcher, Kaliyuga, Clemson, Cyprus and Pere Marquette 18. The point of the little booklet is that if the Meno message 'case had_ been carried aboard some message detail- ing the cause of the disaster might have reached the shore. Some inter- esting experiments have been made e