In fact, there is no central exchange.

上次计算时，光我所知 就有48个不同的线上市场。

It was Mr. Scribner also who replaced the individual system of dry cells with one common battery located at the central exchange, an improvement which saved the Company 4,000,000 dry cells a year.

也是 Scribner 先生用位于中央交易所的一个普通电池取代了单独的干电池系统，这一改进每年为公司节省了 4,000,000 个干电池。