418 VALUATION, DEPRECIATION AND THE RATE-BASE 
TABLE 30. THE PROBABLE USEFUL LIFE OF VARIOUS 
ARTICLES 
Description. eee] Rogdus Authority. Remarks. 
Years 
Accumulators............... 15 Hammond Jour. Inst. Elec. Engrs. 
15 Parsons Jour. Inst. Elec. Engrs. 
15 10% Preece Report Bristol Corp., 1906. 
Airbrakes. ul lL JE 20 Wis. R. R. Com. Quoted by Henry Floy. 
Air compressors............. 20 5% P.G.&E. Co. S.F. rate hearing, 1913-14. 
20-25 Trac. Val. Com. Chi. Con. Trac. Co. Case. 
Are lamps. iste ol 63 Arbitrators Ata. St. Lgt. Contrvsy, 1899. 
12 5% Preece Report Bristol Corp., 1906. 
121 St. Louis P. S.C. Union E. L. & P. Co. Case. 
15 Wis. R. R. Com. Quoted by Henry Floy. 
15 P. G.&E. Co. S. F. rate hearings, 1913-14. 
Arclamp posts. ............. 40 5% Preece Report Bristol Corp., 1906. 
Ammonia concentrators and 
IERES ied ST LR 15 Wis. R. R. Com. Quoted by H. A. Foster. 
Belling. tui ss ee 8 P. G.&E. Co. S. F. rate hearings, 1913-14. 
20 Wis. R. R. Com Quoted by Henry Floy. 
10-20 Wis. R. R. Com Mil. 3¢ Fare Case. 
with shafting and ropes... 15 Chi./U. 7. Co. Chi. Con. Trac. Co. Case. 
with shafting and ropes.... 20 Stone & Webs. Chi. Con. Trac. Co. Case. 
(eather). iv. Latah lil Ee g0-23 Foster ‘“ Eng. Valuation,’ etc. 
Benches (gas plant). ......... 25 Wis. R. R. Com Quoted by H. A. Foster. 
Blowers (gas plant) .......... 15 Wis. R. R. Com. Quoted by H. A. Foster. 
20 P.G.& E. Co. S. F. rate hearings, 1913-14. 
BOIlers. cnr ere ar el 10 Arnold Coney Isl. & Brooklyn Case. 
15 Chi. U. T. Co. Chi. Union Trac. Co. Case. 
15 Alvord Aver. 32-Proc. A. W. W. A. 
15 St. Louis P. S. C Union Elec. L. & P. Co. Case. 
12-16 Metcalf Trans. Am. S. C. E., 1909. 
16.7 Dodge Mt. Vernon W. W. Ill., 1906. 
15-20 Wis. R. R. Com Milwaukee 3¢ Fare Case. 
20 Stone & Webs. Chi. Union Trac. Co. Case. 
20 o% P.G.&E. Co. S. F. rate hearings, 1913-14. 
20 Hammond Jour. Inst. Elec. Engrs., 1907. 
10-28 Chi. Trac. Com. Chicago Trac. Com., 1908. 
25 Williams Galena Appraisal, Kan., 1905. 
25 Burdick Mt. Vernon W. W. Ill., 1906. 
28.57 Arnold 4 Chicago Appraisals. 
25-30 Trac. Val. Com. Chicago Con. Trac. Co. Case. 
30 Kiersted Galena Appraisal, Kan., 1905. 
25-40 Rosecrans (Galena Appraisal, Kan., 1905. 
water-tube...... Ln 20 Floy ard Ave. Case, N. Y. 
water-tube.l.. LLL 00 20 | Wis. R. R. Com. Quoted by Henry Floy. 
water-tube.l.. 1.0 oa 25 5% Preece Report Bristol Corp., 1906. 
water-tube........ 0. LLL 20-30 Foster “ Eng. Valuation,” etc. 
fire-tube. if... kh 10 Arbitrators Ata. St. Lgt. Contrvsy, 1899. 
firestube. ll oi call EE To-15 Foster * Eng. Valuation,” etc. 
fire-tube electric light..... 16-30 Wis. R. R. Com Quoted by Henry Floy. 
fire-tube water works..... 20-25 Wis. R. R. Com. Quoted by Henry Floy. 
Lancashire. atl Sal 22 3% Preece Report Bristol Corp., 1906. 
boilers and accessories..... 20 S.J.L.&P. Cor. Cal. R. R. C. rate hearings.