Since this 1651 work by George Herbert has been mentioned a few times now I thought a translation would be in order.  While an English speaker like myself might come up with something like "sensible darts" I contacted Iain Campbell, this site's Latin expert, for something more definitive.  He responded as follows:

Jacula, would have been iacula, is the plural of iaculum meaning "darts," but could be used more figuratively to mean "short pointed comments" as well as literal projectiles (The shortness is important.  The longer spear was a pilum) 

Prudentum, is probably where you are getting hung up.  It is the genitive plural of prudens (a judicious man/woman), meaning therefore "of judicious men/women" (Note that "man" at that time would be read to include "woman" though in this particular declension, there is no difference between the masculine and feminine).  So, putting the two together, you get something like "short and pointed remarks made by judicious men;" what we would call "aphorisms" I think.