Popular Science Monthly/Volume 70/June 1907/Notes on the Development of Telephone Service VII
|NOTES ON THE DEVELOPMENT OF TELEPHONE SERVICE|
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
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
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:
|165||lbs. No. 12 galvanized B. B. iron wire||$6.80|
|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:
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:
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:
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,
Eight years later, that is, in 1875, David Brooks wrote:
In 1880, the parent Bell company issued further instructions that it believed would be of service to the operating telephone companies, stating:
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
|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.