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- STUDYING THE WATER-TUBE BOILER. “Yarrow & Co., of Poplar, England, conducted last month a series of experiments with water-tube boilers, the results of which they have recently made public. They have for some time past cherished the theory that by applying heat to the pipes used for the downward flow of water, the circulation is increased, and not re. tarded, as is the popular and apparently quite natural supposition. ' The experiments were nine in number, the first four _ of these being arranged to show the methods of indicat- ing the comparative rapidity of flow of water, or of water and steam. In thecase of the first three, this was indicated by a pointer actuated by a grooved bob, which, on a current being set up, pulls on the end of the FiG. 2. arm, and causes the pointer to move along the scale. In each of these cases it was satifactorily proved that the addition of the heat to.the down tube increased the circulation, but no exact rok a was attempted. In experiment No. 4, by the adoption of a screw of certain pitch introduced into the current which was de- vised to actuate a wormwheel attached to a counter, the speed of the current could be ascertaiued. ; The next experiment, No. 5, was specially interesting, and is illustrated by Fig.1. Here we have six Bunsen burners and two glass tubes, the burners on the up tube -being the largest. Circulation was started by lighting the burners to the up tube, and afterwards those on the down tube. It was found that the heat on the down FIG. 3. tubes increased the circulation, as shown in the prelim- inary experiments. The next experiment more nearly approximated to the design of a Yarrow boiler, as is illustrated in Fig. 2. This was composed of three tubes, the lower parts of which were of copper and the upper parts of glass; each led into a drum at the top, and communicated with each other at their lower ends. In this case the Bunsen THE MARINE RECORD. = wu eee eETereT é®&TCODBDMHauDuu(« »«EG SS burners were placed at one side of the casing, the flame Ppiaying on the outer tube, and the heated gases-then passing the other two tubes on the way to the cylinder shown. On the burners being lit an upward current was set up in the tube nearer the flame, the, others act- ing as downcomers. is As the heat increased the two nearest tubes had as- cending currents, whilst the third tube brought down all water necessary for efficient circulation. In the next case illustrated another three-tube model was shown, but two of these were in front of the casing and one at the back, each heated by a multiple-flame burner. The results shown here were similar to those obtained in the preceding case. Following this, some experiments were given in an- other room showing the forcing of air into the glass tubes, either separately or simultaneously, and the ef- fect on the circulation, which was most interesting. The next was the most crucial experiment of all. In this instance, it will be seen from Fig. 3 that, whereas in the former model the receptable at the top was open, in this case a closed drum was used. The two tubes were connected at the bottom by a U piece, and at a convenient height glass tubes were inserted to enable he circulation to be witnessed. : By the application of three small burners to one tube circulation was started, after which the five large burn- ers for heating the tube forming the other leg of the U were brought into play. It was then found that the cir- culation was greatly increased, and continued in the Same Girection, the more highly heated tube acting as the downcomer. Asa final test in this case,steam was generated to a pressure of 150 lbs., when the three small lamps to the uptake pipes were extinguished. Then the current of steam and water continued to circulate in the FIG. 1. tube which acted asa downcomer, although the whole of the heat of the five large Bunsen burners were ap- plied to this tube, whilst the others were extinguished. All of the foregoing experiments were conducted in rooms adjoining the general offices of Messrs. Yarrow & Co.; the remaining tests were given in a more extended form in the boiler-shop of the works, where furnaces were brought into use and the effect of forced draught - on boiler tubes demonstrated, all of which proved most successful, the final demonstration showing that the ex- pansion and contraction of the straight tubes as em- ployed in a Yarrow boiler is not so great as to set up detrimental action in the shape of leaky joints, as at ne time ant icipated. This and other experiments prove conclusively that so long as there is a good circulation, no possible objec- tion can exist to the adoption of straight tubes, owing to the imagined necessity to allow for variations in length due to differences in temperature. This and other kindred features, proved by long experience and continued experiment, will in the near future be fully dealt with by Mr. Yarrow in full detail in one or more valuable contributions to our leading scientific institu- tions, when the opportunity will serve to again return to this most interesting subject. +29 0 ee ee The Deep Waterway Commission has requested the co-operation of William Pierson Judson, C; -E., of Os- wego, in making a compilotion of the existing notes ond maps of parts of the Oswego-Oneida Mohawk valleys ship canal route, and to make such rapid surveys of the remaining parts as he may consider necessary to show what natural advantages the route offers, and whether they are worthy of an expensive and elaborate survey, such as is to be provided by Congressman Chickering’s $100,000 bill, now pending. NEW INVENTIONS. ‘ JohnG. Haentges, of Buffalo, has obtained letters patent (No. 554,680) on a Crib for Building Piers, etc.,for which he applied Sept. 3, 1895. ‘The device consists’ of two parallel series of side sections, grooved bars sub- stantially as above described for securing the sections end to end together, vertical bars secured parallel with each other in pairs to the inner sides of said sections, each one of a pair having a side flange extending toward the flange in its adjacent bar so as toleave a nearly inclosing groove extending from the top to. the. bottom of the two bars, in combination with transverse bind- ing-bars having ends adapted to fit the grooves, for se- curing the sides of the crib. Mr. Haentges has also patented (No. 553.681) means for utilizing currents of rivers, which consists of a number of endless belts moving parallel to each other across which a series of paddles are fixed ‘These are connected by the shaft of one of the pulleys over which the belts operate, with a belt wheel from which the power obtained by the action of thestream against the paddles is transmitted. "Daniel Pike, of New Orleans, has patented (No. 555,- 018) a Device for Launching Boats, application having sbeen made June 24, 1895. The claim is as follows: The combination with a boat having its water-tight tanks or compartments B provided with the slots 4, of the hoods fixed tosaid tanks and having slots in- align- ment with the slots 2 therein, the longitudinal bolt or rod &, an operating-lever connected to said rod, the ver- tical arms arranged in the tanks, with their lower ends fastened to the rod or bolt E, and having their upper ends passing through the slots 4 and housed within the hoods, and coupling pins fitted to the upper ends of said vertical arms and arranged within said hoods, said pins adapted to be projected across the slots in the hoods or to be wholly withdrawn into the hoods. 2. The combination, with davits, of a coupling-bar supported by saiddavits and provided with a longitu- dinal divided slot and with a suitable guide, », near one end, the sets of guide-sheaves within the divided slot of said bar, and the cables or ropes T, U, having the hooks ?, “, and arranged on the guide-sheaves and in the guide Z. ee No. 554,434 protects a Rigging Stretcher, and is the fruit of the brain of Hans H. Pickenpack, Brooklyn, N. Y., application having been filed May 25, 1883, and re- newed August 3, 1895. The claim is for the combination pes C009 Gove of two plates having each a longitudinal series of holes, one of said plates being adapted to be connected to one part of the rigging to be stretched, a thimble-head se- cured to the other of said plates and adapted to be en- gaged by a loop of the other part of the rigging to be stretched, said thimble-head having a bearing for en- gagment with the loop of the rigging which is inclined across the plane of the plate to which the thimble is at- tached, whereby the standing parts of the loops are brought into line with the other of said plates, and means to fasten the said plates together.