Physicists and mathematicians applaud Huygens' work on the pendulum.  He recognized its path to be that of the much studied cycloid.  For this reason, the cycloid is sometimes called the tautochrone.

Huygens also investigated refraction of light in crystals.  This was to become an enormous field in chemistry.

Though brief, his De Ratiociniis in Aleae Ludo or On the Calculations in Games of Chance (1657) is considered the first text written on probability.