Errors in the Date of Printed Books

In the title-page of Peter Heylin's *Microcosmos*, 8th ed., the date is printed 1939 instead of 1639. In like manner, in *Historical Applications and occasional Meditations upon several Subjects, written by a Person of Honour*, printed in 1670, the imprimatur, signed "Sam. Parker," is dated 1970, instead of 1670. In each of these cases the error is evidently caused by the compositor having inverted the figure 6, which thus became 9.