About this time, too, the rising young mason began to feel that hemust get a little more accurate scientific knowledge. The periodfor general study had now passed by, and the period for specialtrade reading had set in. This was well. A lad cannot do betterthan lay a good foundation of general knowledge and generalliterature during the period when he is engaged in forming hismind: a young man once fairly launched in life may safely confinehimself for a time to the studies that bear directly upon his ownspecial chosen subject. The thing that Telford began closely toinvestigate was--lime. Now, lime makes mortar; and without lime,accordingly, you can have no mason. But to know anything reallyabout lime, Telford found he must read some chemistry; and to knowanything really about chemistry he must work at it hard andunremittingly. A strict attention to one's own business, understoodin this fairly broad and liberal manner, is certainly no bad thing forany struggling handicraftsman, whatever his trade or profession mayhappen to be.