Thomas P. How, of Randolph, ?. Y., has made an improvement in the wheel pen for dotting lines in mathematical drawing, which it is thought will much increase its value. These pens have heretofore been used by but few, in consequence of the work performed by them being imperfectly done. The improvement consists in a peculiar attachment to one of the lips of the pen, by which the pen becomes more perfectly governed and guided by the rule, being prevented from springing, and still allows the wheel to have free play when in motion.