Sentence:  In case any of the committee do not understand what is meant by a rate per <WSD>line</WSD>, I may say that buttons, being very small, are not measured by the foot or inch, but by the line, a line being one-fortieth of an inch. For example, that is a 27-<WSD>line</WSD> buttonnb.... 
Meaning of the word marked with <WSD> tags:  One fortieth of an inch.