Sayfadaki görseller

and it had been his business to try and find out what were the facts in the case-he found that those who had been educated to the use of the plane table think that is the only way to do it. He believed he had never found an exception to that rule. On the other hand, those who have been educated and have had long use with the stadia and transit, think that is the only proper way. He had never seen an exception to that rule. Now, there have been some who have been trained in both methods who give them about an equal showing. The speaker inferred that the author had been educated on the coast survey, and he had never seen a man who was educated on the coast survey who would admit that there were any other methods than those of the coast survey. However, the coast survey was now adopting the steel tape, which had long been used by other government departments, and it had been forced upon the coast survey by a man who had long been connected with the United States Lake Survey. It was tried with a great deal of reluctance; there was in fact a great deal of sneezing at the steel tape by the coast survey assistants. He knew something about Mr. Woodward's troubles there in this matter. The speaker thought there was not only very great ability on the coast survey, but that there was a great amount of prejudice against anything that originates outside of that service.

He fully believed in the efficiency of the planetable, but what is the situation in the west? In the east men are fitted perhaps for government surveys. In the west it is rare that a young graduate finds employment on these government surveys, except it be work on rivers and harbors where the plane-table is practically never used at all, and where the transit and stadia are used altogether. Probably all were doing the right thing. The speaker taught the plane-table method somewhat, but the time is too short to teach both methods thoroughly. He did not seek to fit men for the government service especially, but for such work as comes along in a civil engineer's practice, and possibly in city engineering. The man engaged in city engineering has some little topographical work to do, there are some new conditions to meet, some sewers to be put in, etc. He has his transit, and all he has to get is a couple of stadia rods. That instrument is always at hand, and it is much easier for civil engineers to provide themselves with these stadia rods than with plane-tables which are not useful in any way except for topographical work.

The speaker said in closing that he thought he had never seen field work so well presented, and apparently so well done as it was evidently being done by the Massachusetts Institute of Technology. He was very much gratified by it.

PROFESSOR HUMPHREYS said he was thinking when the author of the paper was describing the work of the student who devised the apparatus for stretching the tape, that possibly the young man had read Professor Johnson's book, in which the same problem was solved in very much the same way. In regard to driving stakes and nails, of course there was a good deal of labor in preparing the line beforehand, but in about three quarters of an hour on the occasion of the very first measurement of a base line that was ever made by this method, they measured two miles. The advantage of having the line prepared in advance so as to use the minimum amount of time in measuring it, being that they can take advantage of the most favorable conditions. As the author said, the most difficult problem was to determine the temperature of the tape. If that cannot be done, the temperature of the thermometer can be found, and a time must be chosen when these will be as nearly identical as possible. At night fair results can usually be obtained. Of course a drizzling rain offers the best conditions.

He agreed with what Professor Johnson had said in regard to the jealousy between the engineers of the coast survey and others. He believed the steel tape was forced upon the coast survey because they could not do without its use without making themselves ridiculous. The stadia method had been used exclusively on the Great Lakes, and he thought they will have it on the coast survey before very long, but he did not think they would give up the plane-table. With an accurate transit vertical angles can be read with a great deal more accuracy than with a plane-table.

PROFESSOR MERRIMAN remarked that, judging from his own experience, nineteen out of every twenty engineer graduates, during the first ten years of their practice, never see a plane-table. They are connected with all kinds of miscellaneous work, and, therefore, it was his opinion that the method with the transit and stadia in topographical work was far more advantageous.

In regard to the use of the plane-table on the coast survey, it seemed to him that if the coast survey, instead of having used it so much, had used the transit to supplement it, it would have covered a great deal more ground at less expense, and the control of the interior space of the whole country would not have been transferred to another department at great expense.

As to the methods of instruction, he believed in everything that had been said except one, namely, that the instructor should be in charge of a party of two or three. It seemed to him, in that case, the instructor would do most of the work. As soon as the men oegin to do work that is not quite right the instructor sees it and puts it right. It is a great deal better sometimes for the student to go on for awhile and make errors and afterwards discover them, than it is for the instructor to follow him so closely. It seemed to him that in measuring the angles at one of those stations, if one man were sent out alone without an instructor, the drill received would be a great deal better in many respects, and that the field work should be divided up so that the students themselves would form heads of departments, each one under the direction of its chief, trying to do its best work.

He could only say he had been very highly gratified at the presentation that had been given of the work that had been done, and especially desired to congratulate the author on the excellent manner in which he had presented it.

PROFESSOR RICKETTS thought the section was deeply indebted to Professor Burton for his very valuable and interesting account, and he had nothing to add to the technical discussion, but he would like to add his testimony to the value of vacation work. By throwing the surveying into the summer vacation the schools were able to get more time for other subjects during the academic year.

At Troy they require every member of the sophomore and junior classes to take a summer course in surveying, generally in the Adirondack region, for one month, from June 1st to July 1st. They work six days in the week and ten hours a day in the field for a month, and at night make their maps and work up the notes. The work is made as practical as possible. Of course, in the mean time during the first two years, the students learn the use of the ordinary surveying instruments so that when they go to the field they are fully prepared to use them. They also require a thesis written by every member of each class during the summer vacation, and it seemed to him that that was quite a valuable addition.

PROFESSOR TALBOTT was glad to learn that the gentlemen were teaching their students to make their own checks in the carrying out of their work, and there was another point in that connection that had not been mentioned. The first time that a young graduate goes out to do work for himself, if he has not

« ÖncekiDevam »