１９１５年以降の電灯のガス灯に対する優位の原因は、発送電技術の進歩と電力会社間の激しい競争、タングステン電球の登場であった。加えて、第一次大戦の影響によって原料炭価格が高騰しガス料金が引き上げられたこともあり、ガス会社は徐々に照明市場から撤退し熱需要の開拓に方向転換を強いられた。東京では、段階的に電灯料が引き下げられたとはいえ、ガス灯と石油ランプに対して電灯料金は相対的に高かった。よって消費者が照明を選択した際には、取り扱いの利便、安全性、清潔性も考慮されたと思われる。
The reason for the superiority of electric lamps over gas lamps after 1915 were the development of generating and sending electricity, competition between electricity companies, and appearance of tungsten lamps. In addition, gas rates were raised because the price of coal rised sharply influenced by World War I, therefore resulting the gas companies to withdraw from illumination market and were forced to exploit heat market. In Tokyo, although the electric lamp fee was reduced gradually, the its fee was relatively expensive compared to the gas lamps and oil lamps. Therefore, when consumers chose illumination, they also seem to have considered the ease of handling, safety, and cleanness.
