Page:Indian Journal of Economics Volume 2.djvu/40

S2'?NLEY JEVONS faster method. Consequenfiy ?hese examples serve to show ?he exten? of ?he increased c?pi?al outJ?y which m? 3 under ordinary circumstances be remunerative by. reducing loss of interest. Under o?her circumstances ?he figures m?y vary indefinitely, ?nd e?ch c?se will require separate calculation principles here se? forth. in accordance wi?h ?he In addition to ?unnels and bridges, and other essen- psr?s of railways, we may no?e ?he following ss s few more examples of ?he kinds of eases in which ?his principle needs to be kep? in mind. In an irrigation canal system ?he building of ?he weir $? ?he head works migh? t?ke much longer ?hsn ?he con- struction of ?he canal i?self and i?s distributaries, sud increased expenditure 'to accelerate i?s completion might? be justified. Again, s coal-mine csnno? begin raising eosl until s second shaf? for ventilation and emergency exi? pt?rposes is completed; and $ more cosfly method of sinking which saves time may prove highly remuners- five. Suppose, again, ?hs? $ new large factory h?s been entirely equipped, bu? ?hs? s vit, sl psr? of ?he engine is found to be broken or de[eefive, i? will s?ve money to obtain ?his in India, paying, if necessary, tmu or. ?wenty times ?he price which i? would be necessary to pay to obtain i? from Europe in ?he ordinary course sfber s lapse of '?wo or ?hree months. The general principles desl? wi?h in ?his section are s?riefiy of s mathematical character, and ?he differentb cases could be calculated from suitable formnlra if ?11 ?he dst? were given. I? wo?ld be outside ?he scope of my presen? purpose, however, 'to go minutely into the subjec? here; and i? will sul?ce if I give ?he following rule which may be useful to guide engineers and 8dministrsfive ol?cers engaged with large projects :-- /?u/?:--The value of additional speed ?n construe. tion--ths? is to say, the rsfio of percentage inemsse