The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

inders, he will find that with the same set in: the throttle, and same revolutions, the mean effective pressure on a given cylinder on = successive runs varies in the most remarkable manner, without any explanation, the steam pressure the same, throttle opening remaining the same, the revolutions the same, and: ey- ery factor which may affect the steam pressure may be the same, but yet the average steam pressure on_ successive runs appears to vary. I think the main factor of uncertainty in the trials in the navy is not speed in revolutions, but in connection with the power. The. president: .Mr. Post, may . I ask you to say something on the sub- ject of trial trips. A TRIAL TO -THE SHIP BUILDER. Walter -A: Post: I do not think I can add very much to what has been already said. The importance of the subject, of course, appeals to every ship builder. Trial trips are a trial to the ship builder, and as Col. Stevens has indicated in the paper, the govern- ment does not pay for all the trial trips of a government ship, nor pay completely for any trial of a govern- ment ship. The government simply prepares the course and. furnishes the observers, and the ship builder does the rest. . Mr. Taylor's description of the way the government trials are now con- ducted agrees exactly with my own in- formation on the subject. I might say I have seen trials run, where one of the runs was a failure, and yet a very good curve gotten. There was no ob- jection raised to it on the part of the builders or the trial board. As to the Rockland course, my in- formation agrees with Mr. Taylor's pretty closely as to the effect of the current, only my idea of it was that the maximum was about 9/10 of,)a_ knot, but the direction of the current. varies several times during a trial, and is very arbitrary in its variation. I do not know that there is anything more that I can add to the subject. | GOVERNMENT. MILE COURSES. . William J. Baxter:- In addition to the different courses mentioned by Mr. Taylor, I can add that there are two government mile courses in the North tiver, which have been used very fre- quently for small boats, principally launches, and the exact location of these courses. I will append .in the printed discussion. W. Carlile Wallace: I am_ inclined to agree with Mr. Taylor in his state- Ment that the liability to error in the diagrams, in getting the power is 8reater than the liability to error in the Speed. At the same time I think if cause of the loss of the run. TAE-Marine REVIEW Proper care is taken, and proper ar- rangements made beforehand, that the power can be accurately obtained. For a number of years I took charge of the diagram staff in the Denny Co., and as you all know they were the first to introduce the progressive trials, because it was necessary to be careful before the trial that the indicator springs were all in proper order, that the indicators themselves worked prop- erly, and then he got down to the ar- rangement so that we had a man at every cylinder, whether a twin screw or otherwise, we always put a man at every cylinder. At the time of going on the mile, or just before going on the mile, the telegraph rang down so as to give the "span by" and then at the moment of going on the mile, the tele- graph again rang, and they at once started to take diagrams, at the same time taking the counters on the en- gine, and during the run, unless it was a very high: speed boat, we gen- erally managed to get three or four cards from each cylinder, examining the cards carefully to show the pres- sure under water, or atiything that would cause a bad diagram, and in that way we got very fairly good results. I think it is necessary, if you want to get the results with every possible care, to have a really efficient man at your indicators, because the liability of water, and one thing and another, is, very great. that did not come inside of my work at all. That was the work of the reg- ular staif. THE ROCKLAND COURSE. The President: The chair apologizes for taking an undue part in this dis- cussion, but cannot lose this opportun- ity to complain about the Rockland course. It has been my duty to very carefully study this subject, and while the Rockland course is a magnificent one, so far as concerns the area and depth of water available for the ma- neuvering and the running of the ves- sel, the marks are exceedingly objec- tionable, and are the most frequent The landmarks in the mile have only a land background, and after the sun has passed the meridian they become almost In the winter, with a snow invisible. is not , de- background, the difficulty 1 creased over that of occasional houses and barns and pine wood which occur in the summer time. It seems to me it is the plain duty of the government to make these marks large enough and distinct enough to avoid the missing of the marks by five separate observers. Joseph H. Linnard: I think we all recognize that some of the marks on In regard to plotting the curve . think 23 these courses are not what they should be, but contrary to the generally re- ceived opinion, the government has sometimes financial difficulties in ob- taining any funds, or the funds which are available, for the purpose of mak- ing these necessary improvements. I. cannot, of course, speak for the navy department authoritatively, but I have not the slightest. doubt that any ship builder or other person who is interested in any particular course, any trial course, those mentioned in the discussion, used by the navy department can obtain full data with charts and all other available information, so they can run their own trial trips, by addressing the navy department on the subject. There is nothing confidential, as far as I am aware, about the courses, the laying out of the course and the exact length between the different beacons, which of course, as a rule are not ex- actly one mile, and I have no doubt that all this information can readily be obtained on application, for any le- gitimate purpose. IMPROVING GOVERNMENT COURSES. D. W. Taylor: I agree in the ref- erence to the Rockland course, and the remarks concerning its being susceptible to improvement, although I do not be- lieve there is a case where five ob- servers missed a mark. I have an im- pression that the government made an attempt several years ago to improve this course, to improve the marks on the course, and the difficulty was to some extent financial They did not make an arrangement for a black mark on the north end. On the south end the land is' comparatively low, and it would be possible to bring the marks up high enough to show against the sky line, which is the desired condition. At the north end there is a small mountain in the way, and it would be probably very difficult to erect a signal to show above the sky line at that point. I it would be necessary to buy land to get a satisfactory mark high enough above the surrounding country to be perfectly distinct. I believe if 'it had 'not been a case of holdup, the difficulty in making the necessary ar- rangement of marks on that course, would have been overcome. If Mr. Woodruff was here he could tell you all the details of that matter. The President: Mr. Taylor unfor- tunately doubts the statement made from the chair, of an instance where five separate observers lost a mark, and I can only say I have held my breath on the mile--but fortunately speeds are now coming up so that. it is not as diffi- cult as it. was then--but that trial was in the case of the Rhode Island, which