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December, 1909 try his propeller, and they turned the Ericsson propeller down. It was at this time that Ericsson shook the dust of England from his feet came to the United States. The pro- peller afterwards made a good deal of progress in France, but not much in England. After one of the Smith propellers: had the good. fortune to strike a rock which carried away about half of its surface, the vessel made about two knots more 'speed. Prof.' Herbert' Gi' Sadlert( T>tnder- stand that the society has practically and decided to go to the great lakes next. summer. I believe there is one of the Ericsson original propellers lying on the banks at the lock at the Soo. Screw Boat Vandalia. Chairman Taylor: Is there any further discussion? If not, as a mat- ter of record, but of no particular in- terest, I wish to make a few remarks. I was looking over a scrap 'book last Sunday, which belongs to a member TAE Marine REviIEw of council, Mr. Kirby, and there was a letter from Mr. Ericsson saying that his propeller. was much superior to that. of Mr. Loper, and would finally succeed, and also in this same scrap book were drawings of Erics- son's first.attempt, of the first attempt of anybody, and the drawings were made by Mr. Ericsson, of the engine for a screw boat, built on the lakes, the steamer Vandalia, and' I do not know but that that is the propeller to which Prof. Sadler has referred. There was also in this same scrap book a request from John Fish to Robert F. Stockton to pay some one a certain amount of money, which was due him for work on the steam- boat, and that was back in 1787 or 1788. These little reminiscences of mine have nothing to do with the paper, but it happens that I saw these things last Sunday, and in connection with the paper they become interesting to. me, as 1 'trust. they. are to 'you. The Effect of the Parallel Middle Body Upon Resistance HE second paper was entitled "The Effect of Parallel Middle Body Upon. Resistance,' 'by : Naval Constructor D. W. Taylor. This paper is. best. abstracted in' Mr. Taylor's own words as follows: "The paper gives the result of an investigation into the effect of re- sistance upon full vessels of varying percentages of parallel middle bodies. The data as to the parent form, and the method used 'in the perfection of the models, are given here pages 1 and 2, and in the figures Fig. 1 to Fig. 3. I should like to call ate tention to an error in the table at the extreme end, which was brought to my attention this morning by a member. You will find in the second column, the bottom of the second group of columns, series No. 26, be- ginning model No. 951 and ending model No. 970, the breadths in feet are wrongly given. The breadth for the 3,000 pound model is given as 1.682, and it should be the breadth as given for the 1,000 model, namely 2.913. These breadths are reversed accidentally. Ulpon investigation of the effect of parallel middle body, as stated in paragraph 4, it was found that the wetted surface changed very little indeed, so that for the effect upon resistance, we may practically neglect the variation in the wetted surface due to the variation in the 'length of the parallel middle body. Beginning on page 3, paragraph 5, the question of residuary resistance on. is taken up, and we finally derived Figs. 8, 9 and 10, which really give in condensed form the net result of the experiments. These show that 'broadly speaking, from the point of resistance alone--(and I want to em- phasize that this paper refers to re- sistance alone, and there are many other factors to be considered in the design), for the range of speeds at- tained in practice by full vessels, the optimum length of parallel middle body is, for a longitudinal coefficient of 0.68, from 12 to +16 per cent, but it may be made 25 per cent, without material increase in resistance. For a longitudinal coefficient of 0.80 the optimum length of parallel middle body is from 32 to 35 per cent, but it may be made from 44 to 48 per cent, without material increase of re- sistance. These conclusions apply to values of speed-length coefficient above 0.50. For very low speed ves-' sels, the residuary resistance is such a small percentage of the total that the limits above may evidently be materially exceeded." Discussion on Taylor's Paper. © Capt... W. Hovgaard: This is a paper which I think should have con- siderable interest for .shipbuilders. I think it would add somewhat of value to the paper if further results were given--results similar to those given on Fig. 5, I mean the results for the two other coefficients of fineness. Here on Fig. 5 we find the results 487 for the longitudinal coefficient of 0.74. I think it would be of value to have it also for the two other coeffi- cients if the experiments have been made. ; I would like to know if Mr. Taylor has made any experiments on models with varying parallel middle body, 'but with the same ends. The experi- ments here given relate to varying lengths of parallel body, but at the same time with varying fineness of the end. In the '70's Mr. William Froude made experiments with models, with different ends on the middle body. and then he found that the residuary resistance was the same, that is 'to say, the average or mean residuary resistance was. the same for all these different, lengths of middle body, and that the fluctuations were those due to the wave interference only, so that at a given speed the residuary resistance curve would go in a wavy line above and below a certain line, wholly independent of the length of the middle body. I do not quite understand the way that the different forms are derived from the parent form. It is described at the foot of page 1. Referring to Fig. 2, I do not quite see clearly how the location of the ordinate of the derived form is gotten at, I think perhaps Mr. Taylor might explain that more fully--it may be that. I ought. to see it, but 1 do not quite understand it. Prejudical to Speed. The statement is made on page 3, as follows: "It is interesting, how- ever, to note that at the very high speeds any parallel middle body is - prejudicial to speed, the curves ar- ranging themselves in the order of the percentages of parallel middle body." We might also say that the curves were arranged then in the se- quence of the obliquity, because with the shape adopted the greater the length of parallel middle body is, the greater also is the obliquity, and that, I think, might be expected, that the greater the maximum obliquity of the water and lines at the ends, the greater must naturally be the changes in the velocity of flow past the body, and therefore the acceleration and pressures and wave forms are likely to be increased. : hae Prof. Herbert 'C. Sadler: I think the society is certainly indebted to Naval Constructor Taylor for an- other of his very valuable papers. One of the most important points in connection with this paper is that the displacement has been kept con- stant throughout, also the general