ing its armature, pulls the pen in that direction. In the same way a downward pull of the transmitter stylus gives a downward motion to the pen, and the other movements are the resultant of these two.

The pen being placed in an opposite position to the customary one, and the paper moving to the left, instead of the hand to the right, makes it seem very awkward and difficult to learn to write for the first five minutes, but during the next few minutes the learner sees what is required, and soon writes legibly. In very few cases does this require a half hour's practice, the majority learning it in one half of that time.

It is not an exaggeration to state that they soon find it easier than writing direct on paper. It has its advantages, too, in the simplicity of the instrument necessary for the work. By pulling the pen electrically, by means of the stylus, the writer is not aware that he is at one time exerting a greater pressure upon the carbon disks than at another to form the same letter, and in this way overcoming any changes of resistance in the line or battery, because the movement of the stylus rod where it presses upon the disks is always so small the difference is not discovered.

The characteristics of the handwriting of the operator all appear. If a person writes with a regular rolling hand, he will not be limited for speed. The young men in our New York office easily write thirty words a minute. Others make all the letters of the alphabet in fifteen seconds. Both receivers being adjusted to the same transmitter, the same writing is reproduced on each.

It has been the aim of our company to first perfect what it considered the most simple and practical instrument for commercial use. To this end we have operated them in a small way commercially in several towns during the past year, and had experienced men watch their working in order to thoroughly adapt them for the work which was expected from them. The experience was valuable, and the simple changes required will give us a thoroughly commercial instru

ment.

We are often asked what effect has induction on the writing. So far we have never noticed any whatever. They were tried with the electric wires in subways in London, but the induction was not apparent in the movement of the pen.

At Pittsburg we use poles in conjunction with the electric light

company, and run bare wires among theirs for distances of a mile or more, without the slightest disturbance to the moving pen.

At the close of Mr. Gump's paper numerous questions were asked and answered, after which the meeting was adjourned to enable the persons present to examine the instruments in operation, and also the watchman's clock. Samples of writing transmitted from one part of the room to the other were given to many of those present.

MEETING 379.

The Phonograph and the Phonograph-Graphophone.

BY PROF. H. W. VAUGHAN.

The 379th meeting of the SoCIETY OF ARTS was held at the Institute on Thursday, November 8th, at 8 P. M., Prof. C. R. Cross in the chair.

The records of the previous meeting were read and approved.

The chairman then announced the subject of the evening to be a description and exhibition of the Phonograph and the PhonographGraphophone,-inventions of Edison, Bell, and Tainter. He then explained the acoustic principles involved in the operation of the machines, illustrating his remarks by experiments with tuning forks, organ pipes, etc.

After this explanation the chairman introduced Prof. H. W. VAUGHAN, of New York, who briefly described the principal features of the machines, and indicated some of the uses to which they could be put.

At the close of Prof. Vaughan's remarks a vote of thanks was passed to the speaker for the exhibition. The meeting was then adjourned to give the persons present an opportunity to personally inspect and listen to the machines in operation.

MEETING 380.

The Summer School of Mines.

BY PROFS. H. H. RICHARDS AND F. W. CLARK.

The Summer Course in Topography, Geology, and Geodesy.

BY PROFS. A. E. BURTON AND G. F. SWAIN.

The 380th meeting of the SOCIETY OF ARTS was held at the Institute on Thursday, November 22d, at 8 P. M., Prof. G. F. Swain in the chair.

After the reading of the records of the previous meeting, and the election of new members, the chairman introduced Prof. R. H. Richards, of the Institute, who gave an account of the Summer Schools of Mines.

Prof. RICHARDS said: The Summer School of Mines of 1888 was of a character entirely new to our Institute, although it has been adopted by Columbia School of Mines, and Washington University, for some years, namely, to locate in one spot and to go to work.

The spot chosen by us was the Eustis mine, of Capelton, near Sherbrooke, Canada, a pyrites mine carrying copper.

After providing ourselves with tents and food, we next laid out our work, and it was divided into two classes, one above ground and one under ground. The latter will be described presently by Prof. Clark. Parties were formed of four students each. Two parties worked on the surface and two under ground. This work continued four days, at the end of which time the parties exchanged places.

The work on the surface consisted in examining and describing the methods of sorting and shipping the ore, in making assays of some of the products, and in making a geological survey of the neighborhood. In this survey some two or three hundred outcrops of the ledge were visited, located, and plotted on a map. At the close of the geological work a somewhat novel survey was made. After

determining some hundred or more dips and strikes over a considerable area, to get a reliable average, and assuming that the dip and strike of the copper vein was the same as that of the rock, we made a diagram which gave us the rise or fall of the copper vein at all points of the compass. We then, while running the line, and in selecting each new direction, had only to point the compass in such a direction that the rise or fall of the ground would be the same as the rise or fall of the vein for that hearing. Then, provided our premises were correct, we could follow this line with confidence that we were on the outcrop of the copper vein, even though no surface indication whatever could be found. In this way a line about half a mile long was run through thick forest along the supposed outcrop of the vein. We found little in the way of surface indications on this line until we came to the end of it, where we found a group of costeaning ditches and prospecting pits, which indicated that they belonged to the same copper vein as the mine. Prof. Richards gave some interesting accounts of their camp life. He also expressed himself as being perfectly satisfied that the experience gained by the students was of great benefit to them.

At the close of Prof. Richards's remarks the chairman introduced Prof. F. W. Clark, who gave an account of the under-ground work of the school.

Prof. CLARK said: The under-ground work was divided as follows, each squad worked four days on mine survey, four days on drilling and blasting, two days on timbering, and a day each on track and cars, engine and ropes, and rock drills. After the work common to all was finished, those who chose to do more work of this character located two or three points in the mine on the surface, and several vertical shafts for the future working of the deposit, did additional timbering and other mine work, examined and reported on neighboring mines and works, made a section on the line of two of the slope shafts, etc.

As will be seen by the plan and section of the mine maps, the workings are very irregular and slope at an angle of 35°, but vary from 15° to 70° in different parts of the mines. The deposit varies in thickness from four feet to nearly sixty feet. The roof or hanging wall is supported by timbering and beavy pillars of ore, so that the mine is a very open one.

Great trouble was experienced in holding

stations in many parts of the mine, owing to the great hight of roof and the filling or loose ground under foot. Spikes on studs, drill holes, stake and clay spots on roof were generally used for survey stations. The first survey squad established a base line on surface outside of adit, brought the line in about 1000 feet to slope shafts, then descended on the line of No. 3 shaft, crossed over to ladder way on the opposite of mine, and ascended to starting point. The next squad began at the two lowest stations, and surveyed another loop, finishing at their starting point, etc. Both horizontal and vertical angles were always read, the distance measured in the line of sight, and the horizontal and vertical distances calculated and plotted. If any errors in measurement or calculations were made, the work would not check, and had to be repeated.

The drilling was done in squads of two, one man holding and the other striking. Men selected by the superintendent of the mines instructed the students in the details of the work.

The timbering was done in the same manner, the students helping to take the measure for the timbers, cutting the britches, framing the timbers, and putting them in place with the timber gang.

The boys were very green at first, and amused the old miners very much but in a week they were perfectly at home, and went about the mine with the assurance of old hands, in striking contrast to their first visit under ground. Every one, from the superintendent down, did everything he could to make the visit pleasant, and I think all the miners were sorry when we left.

No accidents of consequence occurred under ground. A few bruised hands and limbs, when drilling, and a few slips while surveying, make the sum total of accidents.

THE SUMMER COURSE IN TOPOGRAPHY, GEOLOGY, AND GEODESY.

The chairman then introduced Prof. A. E. Burton, who gave a brief account of the work of the Summer Course in Topography, Geology, and Geodesy.

Prof. BURTON said: The subject of a Summer School of Topography, Geology, and Geodesy was first discussed at the Institute of Technology about two years ago, and during the winter of 1887 a definite programme of work was arranged, and the course was made an essential part of the geodetic option in the Civil Engineering