A calorimeter is provided for measuring a quantity of heat. The calorimeter has a liquid constrained so as to allow expansion of the liquid solely in one dimension along a single axis such that liquid expansion may be measured on the basis of light impinging along the single axis of liquid expansion by means of a non-contact displacement transducer. Interferometric optical means for remote measurement of multiple microcalorimeters permits parallel monitoring of multiple chemical reactions and the performance of parallel biochemical assays.