420 VALUATION, DEPRECIATION AND THE RATE-BASE 
TABLE 30. THE PROBABLE USEFUL LIFE OF VARIOUS 
ARTICLES (Continued) 
Description. Erect] ST Authority. Remarks. 
Years 
Buildings (continued) 
brick gas retort. ........... 30 Wis. R. R. Com. Quoted by H. A. Foster. 
1st class stone and brick... 75 Wis. R. R. Com. Quoted by H. A. Foster. 
2nd class shops, etc........ 50 Wis. R. R. Com. Quoted by H. A. Foster. 
fireproof... alle 40 0% Chi. Tel. Com. Chicago Tel. Com., 1908. 
reinforced concrete. ....... 50 P. G. & E. Co. Steel r-f., conc. r., and floor. 
foundations... CLC RTO 0% Preece Report Bristol Corp., 1906. 
Cables 
mailing Aur Sc So 30 159% Parsons Jour. Inst. E. E., 1907. 
aisha La 20 Chi. Tel. Com. Chicago Telephone Com. 
armored mains. ........... 25 Hammond Jour. Inst. E. E., 1907. 
SONA TNAINS loa ls lle ale nla 30 Hammond Jour. Inst. E. E., 1g07. 
armored Lali tie LtL 1 35 15% Preece Report Bristol Corp., 1906. 
cables and feeders......... 20 Mil. E. R. & L. Milwaukee 3¢ Fare Case. 
cables and feeders......... I5-25 Wis. R. R. Com Milwaukee 3¢ Fare Case. 
main lead-covered......... 20 26% P. G. & E. Co. S. F. rate hearings, 1913-14. 
subsidiary cables.......... 15 40% Chi. Tel. Com. Chicago Telephone Com. 
aerial LL ak et 15 Chi. Tel. Com. Chicago Telephone Com. 
acrinlilines. a... J 20 St... P. S.C. Union Elec. L. & P. Case. 
aerial exchange. ........... I2-I5 30% Tel. “ Data" Quoted by H. A. Foster. 
aerial lead-covered......... 10-15 Foster “ Eng. Valuation,” etc. 
aerial lead-covered. ....... 15 Wis. R. R. Com Wisconsin Tel. Co. Case. 
aerial terminals........... 12 0% Chi. Tel. Com. Chicago Telephone Com. 
aerial terminals........... IO-I2 Tel. * Data” Quoted by H. A. Foster. 
underground lead covered 20 St. L.P.'S. C. Union Elec. L. & P. Co. Case. 
underground lead covered 25 Wis. R. R. Com. Quoted by Floy. 
underground lead covered. 20 Wis. R. R. Com. Quoted by H. A. Foster. 
underg’d mainexchange.... 20-25 40% Tel. “Data” Quoted by H. A. Foster. 
underground sub-exchange; 13-20 40% Tel. ““ Data” Quoted by H. A. Foster. 
Ol oA hel Ne 30 40% Tel. *“ Data” Quoted by H. A. Foster. 
SUDMATINE. . ue i= elev vives 10 Tel. Data?’ Quoted by H. A. Foster. 
Coal and ash machinery... .... 10 Wis. R. R. Com Quoted by Henry Floy. 
10 Mil. E. R. & L. Milwaukee 3¢ Fare Case. 
14 Trac. Val. Com. Chicago Con. Trac. Co. Case. 
14.2 Arnold 4 Chicago Appraisals. 
15 Wis. R. R. Com Milwaukee 3¢ Fare Case. 
15 Chi. U. 2. Co- Chi. Union Trac. Co. Case. 
20 Stone & Webs. Chi. Union Trac. Co. Case. 
20 Henry Floy 3rd Ave. Case, N. Y. City. 
Compressors (Air) ............ 20 5% P..G.& BE. Co. S. F. rate hearings, 1913-14. 
, 20-25 Trac. Val. Com. Chi. Con. Trac. Co. Case. 
Compressor station 
Natural gas... lores dein 0 | 50% Cal. R. R. Com. Midway Gas Co., et al. 
CONGEUSEYS svi einiee alnis vivininimiminin 10 Arbitrators Ata. St. Lgt. Controversy. 
15 $5.1... P. S.C. Union E. L. & P. Co. Case. 
20 Wis. R. R. Com Quoted by Henry Floy. 
20 Floy 3rd Ave. Case, N. Y. City. 
20 Arnold Coney Isl. & Brooklyn Case. 
20 0% P.G.&E. Co. S. F. rate hearings, 1913-14. 
25 S.J.L.&P. Co. Cal R. R. Com. rate hear’gs.