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Popular Science Monthly/Volume 70/June 1907/Notes on the Development of Telephone Service VII



IX. Telephone Line Construction.

IN 1876 the wires used for telegraph, circuits were usually of iron or steel, because the tensile strength permitted of long spans and comparatively long sag. At that period hard-drawn copper line wire was unknown, and it is problematical whether the volume of traffic passing over the average telegraph wire at that time, outside of the main trunk lines, would have justified the heavy initial investment required to string copper circuits. Thus it came about that iron and steel wires were naturally adopted for telephone lines. About that time George B. Prescott wrote that

a very short experience with, copper line wires both in this country and in Europe, proved that this metal was altogether unsuitable for the purpose, its sole recommendation consisting in its superior conductivity, and it was, therefore, soon replaced by iron wire of large diameter.

But T. B. Doolittle proved how fallacious that theory was, by producing a hard drawn copper wire in 1877, that, as stated in Chapter V., proved of inestimable value to telephone interests the world over.

This failure on the part of soft drawn copper wire to satisfactorily serve as line wire was due to the unpleasant habit it had of not staying where it was placed; it lacked the physical stamina to support itself, and would break with its own weight. This fact was well known to telephone men. Yet few perceived the merit in Mr. Doolittle's improvement, or took kindly to it until forced to do so by later conditions. In 1880, three years after Mr. Doolittle's experimental hard drawn copper line had been strung in Ansonia, Connecticut, a telephone line gang started to string a toll circuit between Hartford and New Britain, but completed less than five miles. This circuit consisted of one No. 18 soft drawn copper 'office' wire, having a double braided cotton covering saturated with paraffine; but by reason of the long spans between the poles the sag was sufficient to cause the small soft wire to break with its own weight. Thus, after spending several days in rejoining broken ends, the circuit was abandoned, and iron wire strung in its place.

In cities and wherever the iron circuits were subjected to the destructive effects of atmospheric action, especially where much bituminous coal was used, oxidization shortened the life of the circuits in the pioneer telephone days, just as now happens thirty years later. The prevailing belief among the early telephone men was that iron wire would have an average life of from fifteen to twenty years. But it only required a brief experience to show that many iron circuits on city pole lines, even of extra best (E. B. B.), had an average life of less than four years, and that rapid rusting rendered some circuits worthless within three years.

For pole lines, chestnut was the principal wood used in 1876, though there were also many white and some red cedar poles used, and here and there a few locust and oak poles were occasionally utilized. The number of poles then placed to the mile varied according to the climate and the breadth of view of the owner. Ordinarily they ranged from fifteen to forty, the average in the northern states being from twenty-five to thirty, according to the downward range in temperature. As a rule, poles 25 feet in length answered every purpose, for there were no other lines to interfere, while 4-inch or 5-inch tops offered sufficient support to carry the few wires required in 1878-80.

Now-a-days the approved practise in building telephone trunk lines is to require selected heavy chestnut or cedar poles, not less than eight inches in diameter at the top, and with a corresponding heavy butt, and in length ranging from thirty to fifty feet, depending on the contour of the country and the number of circuits to be carried. From forty-four to fifty of these poles are placed per mile, while the depth that they are set in the ground ranges from five feet to nine feet, depending on the length of the pole and the character of the soil or rock.

It may be recalled that in the first circular issued by 'the proprietors of the telephone,' dated Cambridge, Mass., May, 1877, Gardiner G. Hubbard stated that

telegraph lines will be constructed by the proprietors, if desired. The price will vary from $100 to $150 a mile; any good mechanic can construct a line; No. 9 wire costs 8% cents a pound, 320 pounds to the mile; 34 insulators at 25 cents each; the price of poles and setting varies in every locality; stringing wire $5 per mile; sundries, $10 per mile.

At the first glance the amount of material shown in that estimate may appear somewhat inadequate, judged by modern methods of standard pole line construction, calling for forty-four poles to the mile. Yet a moment's study will show that the proposed line was substantially planned, was far stronger and would probably possess far better talking qualities than some present day private lines. In an elaborate catalogue issued by a manufacturing telephone company in 1906, twenty-nine years after Mr. Hubbard's circular was issued, the following estimate appears:

To give something of an idea of the expense of building one mile of line, grounded circuit (1 wire), we submit the following items. We do not estimate the cost of poles, which can usually be obtained in your own locality, using twenty-five 25-foot, 5-inch top poles to the mile:
165 lbs. No. 12 galvanized B. B. iron wire $6.80
25 Oak brackets .30
25 Pony glass insulators .37
25 60-penny and 25 40-penny nails .25 $7.72

On February 1, 1878, the Bell Telephone Company of Boston, the second of the parent associations, issued circular No. 3, reading in part:

When the (District telegraph) company does not desire (to introduce) the Bell telephone, a District telephone company should be organized, and metallic circuits constructed, running from the central office to various parts of the city. . . . The stock to be issued for the cost, in any case, should not exceed one hundred dollars a mile of wire, including all fixtures.

Evidently good telephone line construction was considered too expensive to justify introducing the telephone in many places, for one year later, the parent company issued a circular bearing the caption 'Telephonic Exchange System,' and detailing a combination of the advantages of the different exchanges in operation. Therein it barely touched upon the construction of line circuits, but called attention to the now well-known fact 'that repairs on line' are part of the current expense, an item that companies organized during late years have been prone to charge to construction and capitalize. But later, in 1879, the third parent company issued a pamphlet of instructions from which the following item is taken:

The line wire generally used is the No. 12 galvanized iron, and a line built of this wire, if securely put up, will last for years without repairs. Where a cheaper line is desired, No. 14 or 16 iron wire, or a small copper or brass wire may be used, but smaller wires than No. 12 are very liable to be broken by storms and high winds, and it is always cheaper in the end to use wire at least as large as No. 12. In towns or cities the wire can be run over house-tops, using small glass pony insulators and wooden brackets. About thirty of these insulators and brackets are needed for a line one mile long. They can be nailed to the side of a chimney, to the ridge-pole or side of a house, or to a pole. When there are no houses to support the wire, poles must be used. These are generally about twenty feet long, four inches in diameter at the top, and are set four feet into the ground. Care should be taken to keep the wire from touching anything except the glass insulators. The line wire should terminate on the outside of the stations, and the connections be made to the instruments by No. 16 or No. 18 insulated office wire, which is wound tightly around the iron wire and soldered.

Possibly construction of so cheap a character was too costly to meet the approval of many early operating companies, so to meet this uneconomical demand for cheapness regardless of permanency, a new set of instructions was issued by the parent company, which read, in part, as follows:

Lines up to six miles in length can be built of No. 14 galvanized iron B. B. wire. Lines over six miles and not over 25 miles should be built either of No. 11 or No. 12 galvanized iron B. B. wire. Lines over 25 miles in length should be built of No. 11 galvanized iron B. B. wire. We recommend the use of porcelain insulators, they being the best as well as the cheapest. Trees, house-tops and poles can be used in the construction of a line. When fastening a line to a tree, let your wire slack enough to swing to and fro with the tree, otherwise your line will be broken during a windstorm. Tree limbs or branches touching the wire have no bad effect on the telephone, but should be avoided if easily possible. A pole should be set no less than three feet in the earth and eighteen to thirty to the mile. Always try and keep your poles in a straight line.

The flimsy character of such cheap and improper telephone line construction is readily apparent, and we now wonder why the local owners should have been led into such expensive errors. Yet the waste of thousands of dollars in construction of the cheapest character is readily explainable on the ground that few had any faith in the future of telephone service; it was an experiment that might require years to demonstrate its value; thus capitalists refused to countenance the large initial expenditures required in constructing pole lines possessing qualities of permanency and stability.

Again, this kind of line construction was just as good, and in some cases far superior, to that adopted by several telegraph companies during the decade preceding the invention of the telephone. This is shown in the report rendered in 1868, by C. F. Varley, a well-known electrician of the English telegraph companies, who made a thorough inspection of telegraph lines in the United States. Mr. Reid states that this report,

which was very minute and exhaustive, was a startling revelation of the condition of the American wires. The obstruction by imperfect joints, by relay magnets of all grades of resistance, by impure wire, by contact, by defective and neglected insulation was more or less universal. Many of the original wires were small, naked, full of joints made in all conceivable ways, into which the detained moisture ate a path of rust and ruin.

Eight years later, that is, in 1875, David Brooks wrote:

The rates of telegraphing in this country have always been high, yet but few of the stockholders or those who furnish the money to construct the lines have ever received any return for their investments. In most cases the Morse patent was sold to individuals who organized companies, received subscriptions to stock, and constructed the lines, deriving personally large profits thereby. Usually, about three times the amount of money necessary to build the lines was subscribed by the stockholders, and an equal amount of stock was issued for the patent; so that those organizing the companies not only derived large profits from the construction of the lines, but also held the controlling interest in the stock. By this mode of procedure a few individual speculators have each succeeded in realizing far greater profits from the Morse patent than were ever realized by its inventor.

In 1880, the parent Bell company issued further instructions that it believed would be of service to the operating telephone companies, stating:

It is advisable, where there are numerous wires, to have a cupola erected on the roof of the building where the central office is located, and through it the line wires are conducted to the operating-room. . . . The cupola is about six feet square, eight feet high above the eaves, and about eighteen inches more at the ridge-pole. . . . It is better to have the cupola open into the operating room when the room is in the top story of a building, and cleats are fastened round the inside, bored with a number of holes, corresponding to the number of wires required. . . . The wires, after entering are led to the lightning arrester, then run through the holes in the cleats, which run round the base of the cupola, to the ceiling of the operating room, along which they are carried, PSM V70 D526 Telephone wiring through the window.pngFig. 37. on other hard wood cleats, to the switchboard. . . . Where the main lines are not sufficiently numerous to render a cupola necessary, they may be brought through a window in the central office. . . . (Fig. 37.) The line wires are strung on (pony) glass insulators, which are fitted to wooden pins, driven into crossarms. These crossarms are supported on poles or house-top fixtures, which should be run in trunk-routes through the city or town, branch lines being run to any desired point. It is advantageous to use poles wherever practicable, for the following reasons: Pole lines are not liable to interference from householders, being entirely out of their control; they are much more accessible at all times, and when they are out of order at all the trouble is more easily located and removed; the cost is generally about the same, where the number of wires to be carried does not exceed forty or fifty. Poles should be not less than twenty-five feet long, with a diameter of six inches at the top; and should be set five feet in the ground. Before being set up, poles should be carefully stripped of the bark, and, when used in cities, should be painted. It is the usual practise to place all the crossarms on one side of the pole, fastening them with bolts and nuts. It is sometimes, however, absolutely necessary to run house-top lines. Trunk routes should then be selected, and along these routes structures must be erected at an average distance of about three hundred feet apart. Fig. 38 represents a roof fixture, with four cross-bars, each bar having glass insulators on its upper side, and 'hook' insulators on its under side, thus doubling its capacity for carrying wires. Hooks being expensive, porcelain knobs may be substituted for them as an economical measure. (A foot note reads: It is much better to avoid adding hook or other fixtures to the lower edge of cross-bars. It is apt to bring the wires too near together, and cause trouble from 'induction.' It should be done only when new fixtures cannot possibly be erected.) A correct idea of a 'double wall fixture' may be obtained from Fig. 39. It is in many cases desirable to use this style of fixture in preference to a roof fixture, as removing all danger of causing leaks in roofs; or in cases where flat roofs are not attainable, or where the point of support is necessarily a high party wall or the side wall of a building. . . . Bad construction, necessitating frequent clambering over roofs, while it may do no real harm to the premises, annoys owners and tenants, whose condemnations and complaints soon reach the ears of others, and this is apt to put stumbling-blocks in the way of securing permission for entering upon new premises. Besides these reasons, it can readily be seen that work is the cheapest in the end that does not need extensive or frequent repairs.

Only the old-timers can appreciate what endless trouble was caused by careless linemen climbing on the roofs of residences and attaching wires, without consulting owner or occupant. For a costly experience soon showed that many tin or asphaltum roofs that were in apparent good order, before trespassed upon, were punctured or broken by the negligent dropping of a hatchet or other tool, or by heavily walking over weak parts. Then shingles and boards were split by big nails improperly driven to fasten insulator or bracket, bricks were chipped

PSM V70 D527 Telephone wire supports on the roof.png
Fig. 38. Fig. 39.

and paint knocked off. To the owner, the aggravating part was that this damage was not likely to be discovered until the next heavy rain, and then so long a time elapsed between the trespass and the injury that it was difficult to say just who was to blame.

As the number of subscriber lines increased in the early days, the necessity of longer and heavier poles became apparent. Then the use of higher poles resulted in the attaching of more cross-arms to the main line, until finally the principal object of some companies appeared to be to determine how many open wires a pole line could safely carry. For there are records of pole lines in many cities carrying as high as a hundred open wires, while in a few cities from 150 to 200 wires were carried. What is said to have been the largest and highest telephone pole line in the world was erected on West Street in New York City. The poles forming this line were of Norway pine ranging from sixty to ninety feet in height and carrying from twenty-five to thirty crossarms each.