Arizona republican., 1906-11-14
TAKING A CENSUS
 FOR THE YEAR 1920
Forecasts of Telephone Growth-Char- acter Maps on which the Probable Location of Every Line Thirteen years Hence i: Noted.

years Hence i3 Noted.
 Boston. November 3, Special core spondence to The Republicanl.-If it is a delicate job for the Weather Bureau experts 10 forecast the changes of at mospheric conditions a few days in ad- vance, or for the political experts to give good reasons for their ante election predictions. an obviously much more difficult task it must be to fore cast the amount of talking over the telephone wires the American people will be doing 13 years from now Yet that Is line of predictions upon which the engineers of the Bell companies of the United States are just now work ing. As a means of discovering just how the needs of the future can best be met, step by step. the telephone census has become an accepted part of modern telephone engineering. It is probably the only one of its kind to be taken from ter to twenty years in advance. with al solutely completeness of detail
 The plan of work Is thorough and painstaking. Locality by locality the engineers of a company go over their territory and find out how many lines will be needed. say in 1920: where each one of these will probably be located; {; where each exchange should be placed; how many square feet of floor space will be required; how many busy oper- ators will be handling calls Is years from now; what restroom facilities fhaGn regarding the plant down to the min utest details IS carefully forecasted. Guess-work it might seem to the out sider, but it must be guesswork so re- markedly good that no serious mis- takes can be made in the new constrole- ton. year by year.
 The telephone engineer has. for a starter. the carefully tabulated statIs- tics of the growth of his company in recent years. showing how rapidly the number of lines and of subscribers has increased; how the revenue has been affected by extensions of service. by reductions in rates and other causes i: how the average number of messages. originating day by day at each teie- phone station. has varied how the tell traffic has grown in relation to the To- cal traffic. These and an immense number of other statistics form a basis for mathematical calculation
 But office work alone does not satis fy the modern telephone engineers de- sire for thoroughness. The problem must be seen face to face. According ly he sends his young men out into every street of every town in his ter- ritory. These observers make notes as they go about. just as carefully as an assessor would cover his district. but always with an eys to the probable future as well as to the actual present. From the data they have gathered and brought to the office every -soEse ana every vacant lot is plotted on a map. Facts regarding the improvement or deterioration of neighborhoods are mo- ted Residences are divided into three classes; the first those that may fairly be expected hy 1920 to have an average of one telephone line to each house: second. those in which an average O, one line to every other family may be predicted: third, those in which an average of one line to every six famiI- les may safely be predicted. Similarly the places of business are classified in- to single wire groups and two-party wire gruops.
 Out of the character map" thus form ed an estimate can he made of the whole number of lines which each ex- change district should have in 1920 This count is made. not simply on the basis of the yearly increase of the tele- nhOnQ brrt afu growth of each city and town in the district. While it is assumed that a manufacturing center will continue to be manufacturing center. and that q place whose importance is determined by its being a main distributing point will continue to hold that char acter, efforts are made to get a line on the probable standing of each place a decade or more hence. Not all towns of equal popula ton are going to he alike as regards capacity for telephone use Data is gathered from real estate men and others specially interested. The dual- ity of the population which is moving into the different cities is considered. one place. t is assumed, will have in
 
 100 of population. Another. perhaps of the same size. having a different character of population. will be good for only 10 lines per hundred Of popu- lation.
 The number and location of ex- changes has to be predetermined. The web Of lines which may center at a single switchboard is now about 10000 and it is not thought that this number will be greatly exceeded while the length of the operators arm remains as nature established it. Many new ex- changes. therefore. must be built in 13 years, and many a city now having bu; single exchange will be placed upon a ''multi-office basis"
 The switchboards. furthermore. must generally be so located as to incur a minimum of expense for wire mileage Such location can not always be se- cured. once it has been determined approximately where a new exchange must be opened some years hence a study of the real estate conditions n, that neighborhood is made. The land perhaps on the street where the ex- change theoretically should be is al- ready so expensive that it will seen, cheaper in the end to pay a little more Tor the extra wire mileage and locate the buildings few blocks away. Such considerations have constantly to be