one in the evening
`` The next grade of emery , boy , '' was the reply ; `` our task is of course now not to grind the speculum deeply , but to grind out all these scratches till it is as limpid as the surface of pure water . '' `` Do n't look possible , '' said Tom . `` Well , we will try . '' The next morning they worked for an hour before breakfast in precisely the same way , gave a couple of hours to the task after breakfast , two more in the afternoon , and one in the evening -- `` a regular muscle-softener , '' Uncle Richard called it ; but when for the last time the finely-ground emery number two was washed off , and the speculum examined , its surface looked much better , the rougher scratchings having disappeared . Tom was all eagerness to begin the next day , when the number three emery was tried in precisely the same way . Then came work with the number four , very little of which was used at a time ; and when this was put aside for number five , Tom again cheered , for the concave surface had become beautifully fine . `` Two more workings , and then the finishing , '' said Uncle Richard .