Edmond inserted his lever in the ring and exerted all his strength ; the flag-stone yielded , and disclosed steps that descended until they were lost in the obscurity of a subterraneous grotto .

爱德蒙把他的撬棒插进铁环里，用尽全力一撬，大石板掀开了，露出了一个地下岩洞，洞口有象楼梯似的石级，一直向下延伸而去，直至消失在黑暗里。

In summary , as for the six chemical indexes , recycled water irrigation can increase the content of the relevant elements in subterraneous water and soil , but whether the effect is safe requires further study ; as for plant growth , certain chemical elements in recycled water is conducive to plant growth .

综上所述：就本研究的六种化学指标而言，再生水灌溉增加地下水和土壤中相应元素含量，但影响是否在安全范围内，还需进一步研究；对植物生长而言，再生水中一些化学元素有利于植物生长。