Clothes Pin Insulator

CORRESPONDENCE.

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CHICAGO.

Testing Subterranean Wires. — Delusive Long Line Telephone Tests. — A Sanitary Hattery. — Harmless Dynamo Currents. — Convention Telegraphing. — Telephone Securities. — The Street Car Motor Languishes. — Electric Headlights on Land and Water. — An Insulation for Wire Covering Comes to Grief. — A Canadian Clothes-pin Insulator. — More Talk about Official Wire Cutting.

THE custom which now prevails almost universally among wiremen, of testing with a magneto, such as is ordinarily used by telephone companies, recently came near provoking a lawsuit. A piece of underground work was done for a corporation, who refused after its completion to pay for it, on the supposition that the wire leaked to ground. The proof of the statement depended upon the fact that the magneto would ring through the wire, when the distant end was open. It was suggested that perhaps a telegraph relay might work, but it refused. Then a galvanometer was attached in place of the magneto, and this instrument showed an insulation resistance of 1,500 megohms to the mile.

W. W. Smith, of Indianapolis — known among electricians as one who is "always trying things" — sometime since by way of experiment, after having first tested and obtained a well insulated wire, opened it at both extremities of a section a few miles long, and at two points, removed from the terminals, introduced two telephones into the circuit, and was enabled to work perfectly well with these, using no ground at either end of his line. In both instances the static capacity of the wire was sufficient to store either a positive or a negative impulse, which was immediately neutralized by the next, being of an opposite character. All which is given for the benefit of those who test with alternate current magnetos, and to whom I would suggest commutator machines, which, having once filled the static capacity of the wire, will cease to ring provided there is no leak. In several long line telephone tests lately, I notice the terminals of the wire are arranged in the same building. The wire may be very long, but the circuit is metallic, save the short ground connection between the two instruments, and these are frequently on the same general ground wire. Experimenters seem to forget that it makes little difference to a telephone whether the impulses go right or left to line, provided they get back home again.

A novel battery has lately been suggested by a Frenchman, M. Bremond, who proposes the use of the noisome elements of cesspools, sewers and the like, as an excitant of electricity. His plan is to place a cylinder of carbon, surrounded by sesqui oxide of iron in powder, within a porous cell, outside which is a species of iron frame or screen, the whole to be lowered into the receptacle, where sulphureted hydrogen, both as a gas and in solution abounds. The utilization of the waste contained in places of this sort, if these can be made available, would, while being extremely economical, tend also to the purification of cellars and other unventilated places, and open to the demands of electrical science an almost inexhaustible supply in cities where public sewers and drains might be arranged to play the part of huge battery cells, with almost no cost for the production of the current. It is not an entirely new idea which M. Bremond is advocating. Relays and sounders have been operated by batteries of zinc and copper so placed, but the use of these cheaper elements, carbon and iron, I think is a radical departure, under the circumstances.

There are tricks in all trades, and electrical merchandising is no exception. In the course of a discussion a few days since, at which I happened to be present, the question of relative danger from the currents of the various systems was under consideration. "Now, our system," said its advocate, "is so perfectly safe that I can take hold of the two sides of this lamp, burning as it is, without feeling it," and he proceeded to demonstrate by grasping the frame of the lamp. "That's all right," said a bystander, "you hold on, while I raise the upper carbon." He didn't hold on. In this connection the recent experiments of Dr. Stone, as detailed by him before the Physical Society of London, are interesting. Dr. S. claims as the result of many measurements, that the resistance of the human body is usually less than 1,000 and often as low as 500 ohms, and that it is less for currents of higher than of lower potentials. He thinks that an E. M. F. of 100 to 200 volts, under some circumstances, such as contact with moist or tender portions of the body, might produce fatal effects. I have heard of persons who could stand the current from a 50-light machine, but I would rather take their word for it, than to test my capability in that line.

We have just passed through another political convention, with its accompaniments of press, specials, and bulletins. The Western Union. B & O. and the new coalition, were all represented at the convention, and all did good work, and plenty of it. It is estimated that 1,500,000 words were transmitted.

Telephone stocks are not paying well just now, as a rule. The exceptions are the Chicago and Wisconsin companies, both of which remember their stockholders regularly on quarter day. But the Central Union and the Kansas companies forgot their friends in January and July, and the Great Southern T. & T. company, passed its July dividend. They all claim to be putting their money mto extra territorial work, and that the stockholders loss in dividends will be their gain in property. I am not aware that any of these stocks can be had at the present low rates, and I think every holder who can, will continue with the companies until the dawn of brighter days. There is a general faith in the future, when the Drawbaugh squabble shall be settled, and with it all the other "original Dr. Jacobs" are consigned to outer darkness. New inventions and prospective rivals are springing up daily, but I much incline to the belief that any and all these, unless some very radical departure from the electro-magnet principle is discovered, will have to pay the toll of royalty, if ever they cross the bridge to the fields of telephonic installation.

In a recent letter I spoke of a Chicago street car motor, which was in course of construction. Subsequently, I noticed in an electrical journal, a statement that it was in successful operation. The motor was not a success in the first instance, the batteries failing to accomplish the result aimed at. Faure batteries of 16 plates each were substituted. The first essay with these proved disastrous, and the coils were re-wound. The car when I last saw it, was standing upon a track in a coal yard, and had made many trips as far as the gate and back, but I do not think it has ever been used on other than these brief excursions. The inventor has high hopes of his ultimate success, however, and is earnest and persevering.

Woolley's system of electrical headlights for locomotives is being experimented with on the Chicago, Milwaukee & St. Paul road. One of these lights, on engine 541, running between here and Milwaukee, it is claimed is doing good work. I have not yet been able to see it in operation. It is run by a rotary engine upon the same frame as the dynamo, the whole quite compact, about three feet in length, placed upon the running board of the engine on the fireman's side. From there the wires are carried, without extra insulation, around the hand rail to the lamp, which, save being a little taller, looks much like an ordinary headlight. The glass in the front of the lamp, instead of being a solid sheet, is divided by nine perpendicular cuts, making ten pieces, instead of a plate, to compensate for expansion by heat. I presume, or possibly to break up the rays — it would do both, probably. Mr. Woolley will be remembered as the thermal battery man of Indianapolis.

One of the little excursion steamboats belonging here, is carrying a plant of a half dozen lights, one of which is a powerful headlight, placed near the stern, on the upper deck. The frame is so placed that it can be revolved in a horizontal plane, to direct its rays towards the city at any point of the boafs progress. Recently the rays from this light, when some miles out in the lake, were distinctly seen at the western end of the city, projected on the hazy atmosphere, and tearing a perfect resemblance to a comet's tail. The sight was both novel and beautiful, and the light source could not have been less thin 5 miles distant. Very many of the companies here have plants, both arc and incandescent, on river boats from St. Louis to St. Paul.

I mentioned in a late letter, a new insulating substance which was to gladden all our hearts. The promised experiments were made, and I had the pleasure of being a party to them. Never were better materials selected — never manipulations more carefully made — never a result more disheartening! Our insulator was to be flexible, yet solid — impervious to moisture, indestructible by fire. We cooked it by the formula — we tempered and dried it with scrupulous care according to the rule, and waited the requisite time for the action of the re-agents. We tested it. It was hard — hard as a gun-flint. It was not flexible, but broke like gum arabic or raw maccaroni, leaving the wire naked as the lie of which we had been the victims. It was thirsty as a drunkard after a debauch, and, while it would not blaze, would char about as readily as a green twig from a tree. Its value as an insulator for wire, to use a phrenologist's expression, "In a scale of 1 to 7," would be about — minus 1. We are still wantiug a good flexible insulation for covering wires.

Next to the Evansville man who doesn't believe in insulators of any description for telephone lines, comes a Canadian telephone man who uses a form of line insulator of his own invention, and which certainly, for cheapness, simplicity, and ease of installing, is difficult to equal. It may be called the clothes-pin pattern. A wooden pin has a slot sawed in the direction of its length, at the end of which slot the opening is slightly enlarged. Into this he places a bit of soft sheet rubber, and drops his line wire into the slot. The pin, which has a spreading form, is then driven into the cross arm and the whole is accomplished. There is no tie wire, no screw, no anti-hummer needed. The mechanical vibrations are all done away with. Now, if the sulphur in the rubber will only let the iron wire alone, contrary to its usual practice, it seems to me he will have a decided improvement on the standard " drawer knob," and the " low-neck-and-short-sleeve" system in vogue in southern Indiana.

The stringing of a few extra overhead wires to accommodate the press during the recent political conventions, has doubtless reminded the city fathers that sundry wires still remain on the surface of the earth, and that it might be a good plan to officially cut them. If they will exercise a little patience, the telegraph companies will comply with the city ordinance, but it is not a job to be completed in a week or a month.

CHICAGO, July 21, 1884.

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