Chapter 4

On the top of the detaching roller is a large steel fluted roller carried at each end by a small arm called a "horse tail." In the original machine this roller simply kept its place upon the detaching roller by its weight, and when the machine came to be run at high speeds it was found that owing to its lightness the contact thus obtained was not reliable, the flutes or ribs of the roller slipping upon those of the detaching roller, which for good work is undesirable. This is remedied by placing a heavier top roller in the horse tails, which is made with a broader bearing so as to give greater solidity to the top roller. Another good idea we noticed in this machine was in the application of a treble brush carrier wheel, which permits of the brushes being driven at three different speeds as they become worn. For instance, when the brushes are new the bristles are long, and consequently they are not required to revolve as quickly as when the bristles are far worn. By this improvement the brush lasts considerably longer than in any other system of machine. Their speed can also be regulated according to the length of the bristles, and the change from one speed to the other can be effected in a very few minutes.

A common defect in combing machines is the flocking that frequently happens. This is the filling up of the combs on the cylinder with dirt and cotton, which the brush fails to remove. Although in general appearance the cleaning apparatus is the same as the ordinary one, modifications are introduced which make its action always effective and reliable. We were informed by a mill manager, who has a great number of these combers, that he meets with no inconvenience from flocking from one week end to another. Altogether, it will be seen that Messrs. Dobson and Barlow have almost reconstructed the machine, strengthening and improving those parts which experience showed it was necessary to modify. As a result their improved machine works at a high speed (80 to 95 strokes per minute, according to the class of cotton), with great smoothness and without noise, and from the almost complete absense of vibration the risk of breakages is reduced to a minimum.--_Textile Manufacturer_.

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THE MUNICIPAL SCHOOL FOR INSTRUCTION IN WATCH-MAKING, AT GENEVA.

When, in 1587, Charles Cusin, of Autun, settled at Geneva and introduced the manufacture of watches there, he had no idea of the extraordinary development that this new industry was to assume. At the end of the seventeenth century this city already contained a hundred master watch makers and eighty master jewelers, and the products of her manufactures soon became known and appreciated by the whole world.

The French revolution arrested this impetus, but the entrance of the Canton of Geneva into the Confederation in 1814, rendered commerce, the arts, and the industries somewhat active, and watch-making soon saw a new era of prosperity dawning.

On the 13th of Feb., 1824, at the instigation of a few devoted citizens, the industrial section of the Society of Arts adopted the resolution to form a watch-making school, which, having been created by private initiative, was only sustained through considerable sacrifices.

In 1840 the school was transferred to the granary building belonging to the city. In 1842, when it contained about fifty pupils, it was made over to the administrative council of the city by the committee of the Society of Arts. From 1824 to 1842 the school had given instruction to about two hundred pupils. From 1843 to 1879 it was frequented by nearly eight hundred pupils, two-thirds of whom were Genevans, and the other third Swiss of other cantons and foreigners.

The school, then, has furnished the watch-making industry with the respectable number of a thousand workmen, among whom large numbers have been, or are yet, distinguished artists.

The rooms of the granary, where the school remained for nearly forty years, became inadequate, despite the successive additions that had been made to them, and it became necessary to completely transform them. The magnificent legacy that the city owes to the munificence of the Duke of Brunswick was partly employed in the reorganization, and the school is now located in a vast building designed to answer the requirements of instruction. This structure, which is located in Necker Street, presents an imposing and severe aspect. The main building embraces most of the workshops, the office, the library, and the classroom for instruction in mechanics, all of which receive a direct light. At right angles with the main building are two wings. The one to the north contains in its three upper stories workshops occupied by classes in escapements, bezil setting, compensating balances, and ruby working. On the ground floor are installed juvenile schools.

The south wing contains halls for lectures on theory, and two workshops looking toward the north. The ground floor is used for the same purpose as that of the north wing.

Finally, in the center of the main building is a wing parallel with its two mates. It is in this that is located the vast staircase that leads to spacious landings at which ends on every story a large corridor common to all the halls and workshops. It is in this part of the building that we find the amphitheater of physics and chemistry and the laboratories. Here also is located the museum in course of formation (gotten up in view of the historical study of watch-making), and the amphitheater designed for certain public lecture courses.

In the way of heating and lighting all parts of the building nothing has been neglected, and special care has been taken to have the ventilation perfect.

At present the instruction comprises a practical and a theoretical course.

_Practical Instruction_.--This is divided into three sections: (1) an elementary one having in view the construction of the simple watch in its essential parts; (2) a higher section in which the pupils learn to recognize the complicated parts; and (3) a section of mechanics applied to watch-making and to the study of the construction of machines and tools for facilitating and improving the manufacture.

1. _Elementary Section, First Year_.--The pupil must manufacture all the small tools necessary for making unfinished movements; that is, drills, reamers, punches, files, etc. He must then learn to file and turn, and to make use of the finishing lathe with the bow, or of the foot lathe.

In general, the time taken by an apprentice to manufacture his tools is from two to three months, and he can scarcely go to work on the movements before this.

In this class the regular pupils have to execute seven pieces of work in the rough, two for horizontal escapements with key and regulating wheel, and five for various other escapements. Among these there is one for simple repetition and one for minute piece. Aside from the work fixed by the programme, the pupils may manufacture all the other complicated pieces upon obtaining the authority for it from their masters and the director.

The average time employed in performing the work imposed by the programme necessarily depends upon the capacity of the pupil, but we may say that in general ten months are necessary.

_Second Year_.--After executing his last piece of work in a satisfactory manner, the apprentice passes into the class in regulators, where he begins to manufacture the small tools that he will require.

In this work, as in the preceding, he must take all his pieces from the crude metal, and he must do the forging himself, as well as the roughing down, the turning, filing, and shaping, and finally the finishing, without the aid of any other machine than the dividing one.

In general, after eighteen months of work, the apprentice goes to the finishing shop, where the delicate and minute work begins, pivoting, putting the wheels in place, and practical study of gearings. After learning how to divide a wheel correctly, he is set to work on pinions and wheels in the rough, which he must rivet, finish, and pivot according to the different planes of the pieces that have been calculated and executed by him under the direction of the master.

The programme to be followed by the pupils of the class in finishing is, as regards number of pieces, the same as that of the preceding classes, that is to say, seven.

In general, the pupil passes from the class in finishing to the class in dial-trains, where he makes two of these for his pieces--one a simple and the other a minute train. The teaching of this part is very important as regards the manufacture of escapements. In constructing the dial train, the pupil perfects his filing and learns to make the adjustments correct.

The last class in the elementary instruction is the one in escapements (Fig. 1), the programme of which includes several distinct parts: (1) The tools that are strictly necessary; (2) escapement and cylinder adjustment; (3) making the compensating balances for the pupil's pieces; (4) pivoting, putting in place, and finishing the escapements in regulating pieces. Here, as in the preceding classes, the pupils must do all the work themselves. During their stay in the elementary classes the work done is submitted to the director, who examines it and sends it back to the instructors accompanied with a bulletin containing his estimate as to its value, and his observations if there is occasion to make any.

Pupils who cannot or who do not wish to go over the entire field of the programme stop here, and are now capable of earning their living and of lightening the load that oppresses their parents.--_Science et Nature_.

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MACHINE FOR POLISHING BOOTS AND SHOES.

The principle of an apparatus for blackening boots and shoes dates back to 1838, the epoch at which a machine of this kind was put into use at the Polytechnic School. Since then it seems that not many applications have been made of it, notwithstanding the services that a machine of this kind is capable of rendering in barracks, lyceums, hotels, etc. Mr. Audoye, an inventor, has recently taken up the question again, and has proposed to The Société d'Encouragement a model that gives a practical solution of it. The use of this will allow a notable saving in time and trouble to be effected.

This brush (see engraving) revolves around a horizontal axle supported by a cast iron frame similar to that of a sewing machine. Motion is communicated to it by a double pedal, which actuates a connecting rod and a system of pulleys. The external surface of the brush contains three channels in which the foot gear to be polished is successively placed. In the first of these the dust and mud are removed, in the second the blacking is spread on, and in the third the final polish is obtained.

In order to guide the blacking to that part of the brush which is to receive it, Mr. Audoye protects the lower part of the latter by a half-cylinder of sheet iron. On this there is placed a vessel containing the blacking, and into which dips a copper cylinder having a grooved surface. The horizontal axis of this cylinder is movable; when at rest it is so placed that the cylinder is an inch or so below the brush, but when the operator pulls a button that is within reach of his left hand, the axis is lifted, a contact takes place between the brush and the cylinder, and the former is thus given a rotary motion. As the cylinder still continues to dip into the blacking, the latter is thus spread ever the brush.--_La Genie Civil_.

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PERSONAL SAFETY WITH THE ELECTRIC CURRENTS.

_To the Editor of the Scientific American_:

In your paper of the 21st of February there is an article on personal safety with electric currents, by Prof. A.E. Dolbear. He says that a Holtz machine may give through a short wire a very strong current. For if E = 50,000 volts, R = 0.001 ohm, then C = 50000/0.001 = 50,000,000 amperes. Now that is a very large quantity of electricity, and is equal to an enormous horse power. I think the person receiving that charge would not need another. According to Ohm's law, the strength of current is proportional to the electromotive force divided by the total resistance, external and internal. The last is a very important element in the Holtz machine, and will make a big difference in the current strength. Here are some of the results obtained from experiments made with the Holtz machine. A machine with a plate 46 in. in diameter, making 5 turns in 3 seconds, produced a constant current capable of decomposing 3½ millionths of a milligram in a second. This is equal to the effect produced by a Grove's cell in a circuit of 45,000 ohms resistance. The current produced would be about 0.0000044 ampere. That is rather small compared with the Professor's result. Rossetti found that the current is nearly proportional to the velocity of rotation. It increases a little faster than the velocity.

The electromotive force and resistance is constant if the velocity is constant. The electromotive force is independent of the velocity, but diminishes as the moisture increases, and is about equal to 52,000 Daniell cells. The resistance when making 120 revolutions per minute is 2,810 million ohms. At 450 per minute, 646 million.

Taking it at 450, C = 53950/64600000.001 = 0.0000835 ampere, against the Professor's 50,000,000, amperes, and it would be equal to about 0.006 horse power, which I think would be the more correct of the two; calling E equal to 50,000 Daniell cells.

Yours, Respectfully,

E. ELLSWORTH.

Portland, Me., March 5, 1885.

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A VISIT TO CANADA AND THE UNITED STATES IN THE YEAR 1884.

[Footnote: A lecture delivered before the Society of Telegraph Engineers and Electricians, London, Dec. 11, 1884.]

By Mr. W.H. PREECE, F.R.S.

I do not know what the sensations of a man can be who is about to undergo the painful operation of execution; but I am inclined to think his sensations must be somewhat similar to those of a lecturer, brimful of notes, who has to wait until the clock strikes before he is allowed to address his audience.

The President has been kind enough to refer to the paper I propose to give you, as "Electricity in America in the year 1884;" but I would rather, after having thought more about it, that it be called "A Visit to Canada and the United States in the year 1884."

It will be in the recollection of a good many who are present that in the year 1877 I visited America, in conjunction with Mr. H.C. Fischer, the Controller of our Central Telegraph Station, to officially inspect and report upon the telegraph arrangements of that country; and on the 9th February, 1878, I had the pleasure of communicating to the members of this Society my experiences of that visit.

During the present year my visit was not an official one; I went for a holiday, and specially to accompany the members of the British Association, who, for the first time in the history of that association, held a meeting outside the limits of the United Kingdom.

We sailed from Liverpool in a splendid steamship called the Parisian. There were nearly 200 B.A. members on board; and notwithstanding the fact that rude Boreas tried all he could to prevent us from reaching the other side of the Atlantic; notwithstanding the fact that the Atlantic expressed its anger in the most unmistakable terms at our audacity in turning from our native shore; notwithstanding the fact that Greenland's icy mountains blew chilly blasts upon us, and made us call out all the warm things we possessed--I say notwithstanding all this, we reached the Gulf of St. Lawrence in safety, and I do not think that a merrier or a happier crew ever crossed the Atlantic.

There is one very interesting fact that is not generally known, and I certainly was unaware of it before I started, in connection with this particular route across the Atlantic, and that is, that by it the ship passes within only 200 miles of Greenland. The great circle that directs the shortest route from the north of Ireland to the Straits of Belle Isle passes within the cold region, and hence, while you were all sweltering in heat in London, we were compelled to bring out our ulsters and all our warm garments, to enable us to cross with any degree of comfort. The advantage of this particular route is supposed to be the fact that only five days are spent upon the ocean, and the remainder of the voyage is occupied in the calms and comforts of the Gulf and River St. Lawrence. But I am inclined to think that the roughness of the ocean and the coolness of the weather at all seasons are quite sufficient to prevent anybody from repeating our experience.

We arrived at Montreal in time to attend the opening meeting of the British Association; and at Montreal we were received with great hospitality, great attention, and great kindness from all our brethren in Canada, and we held there certainly a very successful and very pleasant gathering. There were 1,773 members of the British Association altogether present, and of that number there were 600 who had crossed the Atlantic; the remainder being made up of Canadians, and by at least 200 Americans, including all the most distinguished professors who adorn the rolls of science in the United States. As is invariably the rule in these British Association meetings, we had not only papers to enlighten us, but entertainments to cheer us; and excursions were arranged in every direction, to enable us to become acquainted with the beauties and peculiarities of the American continent. Some members went to Quebec, some to Ottawa, others to the Lakes, others to Toronto, many went to Niagara; and altogether the arrangements made for our comfort and pleasure were such, that I have not heard one single soul who attended this meeting at Montreal express the slightest regret that he crossed the Atlantic.

The meeting at Montreal certainly cannot be called an electricians' meeting. The gathering of the British Association has often been distinguished by the first appearance of some new instrument or the divulgence of some new scientific secret; but there was nothing of any special interest brought forward on this occasion. The only real novelty or striking fact that I can recall as having taken place was a remarkable discussion that originated by Professor Oliver Lodge, upon the "Seat of the Electromotive Force in a Voltaic Cell."

This was an experiment on the part of the British Association. Discussions, as a rule, have not been the case at our meetings. Papers have been read and papers have been discussed; but on this occasion three or four subjects were named as fit for discussion, and distinguished professors were selected to open the discussion.

On this particular subject, Professor Oliver Lodge opened the discussion, and he did so in an original, an efficient, and in a chirpy kind of manner that took by storm not only the professors who knew him, but those who did not know him; and I am bound to say that I do not think we could possibly better spend an evening during the coming session, or more profitably, than by asking Professor Oliver Lodge to bring the subject before this Society, so as to allow us on this side of the water to discuss the same subject.

Of course the prominent figure at our meetings was Lord Rayleigh; and I do not think that any person could possibly have been present at those meetings of the British Association without feeling an intense personal admiration for this man, and an affection for the way in which he maintained the position of an English gentleman and the credit of an English scientific body, to the astonishment and delight of every one present. Then, again, we had our past President, Sir William Thomson, who was not quite so ubiquitous as usual; he did not dance from section to section as he usually does, but remained as president of his own section, A. I think he only left his section for a day, and that was to attend the electrical day in Section G; but in his own section he brought down those words of wisdom that one always hears from him, and which make one always regret that there is not always present about him a shorthand writer to take down thoughts and ideas that never occur again, and are only heard by those who have the benefit of being present.

The subjects brought forward were not of intense interest. We had a paper by Dr. Traill, describing the Portrush Railway, and there were various other papers; and I can pass over some of the other subjects, because I shall have to deal with them under another head. But while we were in Montreal, a deputation of American professors and members of the American Association came over, and invited a good many of those who were present at Montreal to visit the American Association at Philadelphia. I was one of those who went over to America simply and solely for a holiday, and I am bound to say that I set my face determinedly against going to Philadelphia. I traveled with two charming companions, and we all decided not to go to Philadelphia. But the compact was broken, and we capitulated, and went from the charming climate of Montreal into the most intense heat and into the greatest discomfort that I think poor members of the Telegraph Engineers' Society ever experienced. We entered a heat that was 100° by day and 98° by night; and I do not think there is anybody in this room, unless he has been brought up in the furnace-room of an Atlantic steamer, who can fully appreciate the heat of Philadelphia in these summer months. The discomforts of the climate were, however, amply compensated for by the hospitality and kindness of the inhabitants. We spent, in spite of the heat, a very pleasant time.

Before referring further to the meetings at Philadelphia, I may just mention the other journeys that I took. My holiday having been broken by the rupture of the union to which I have alluded, I had to devote it then to other purposes, and, in addition to Montreal and Philadelphia, I went to New York (to which I shall refer again), from New York to Buffalo, then to Lake Erie and Cleveland, and on to Chicago, where I spent a week or more. From Chicago I went to see the great artery of the West--the Mississippi. I stopped for a day or two at St. Louis. One remarkable fact came to my knowledge, and I dare say it is new to many present, and that is, that the Mississippi, unlike other rivers, runs uphill. It happens, rather curiously, that, owing to the earth being an oblate spheroid, the difference between the source of the Mississippi and the center of the earth is less than that of its mouth and the center of the earth, and you may see how this running up hill is accounted for.