我们仅仅能在白天时候利用太阳光,而在夜间必须借助人工的光源始能得到光线。近世以来,在大小工厂以及住宅里当夜间工作的时候,各地方都使用电灯。电灯是在一八七三年著名的俄国电工学者拉蒂金所发明的。电灯是最新和最方便的光源,既经济而又具有很大能力,这实在是古所未闻的,因此在照明技术上发生了新的变革。从它被发明的那时起,经过了多次的改良,最后才能得到现在我们所使用的这样的电灯。现在的电灯是这样构成的:在玻璃泡的里头有螺旋形的锦金丝,并充满不与灼烧灯丝起化合作用的气体——普通是氮和氩。通电流于灯丝上,大约热 We can only use the sun’s rays during the day, and we must use artificial light sources to get light at night. Since ancient times, electric lights have been used in various places in factories and homes when working at night. The electric light was invented by the famous Russian electrician scholar Ratkin in 1873. Electric lights are the latest and most convenient light source. They are both economical and capable. This is unheard of in ancient times and new changes have taken place in lighting technology. From the time it was invented, many improvements have been made, and finally we can get the electric light that we use now. Today’s electric light is constructed in such a way that there is a spiral of gold wire inside the glass bubble, and is filled with gas that does not cooperate with the burning filament - usually nitrogen and argon. Pass current on the filament, about heat