This paper describes a simple high-pressure mercury-free microcalorimetric technique that enables the compression of a fluid from 0.1 to 30 MPa. Thermal expansivities of several compounds were calculated (n-hexane, cyclohexane, heptane, and toluene) with the pressure. scanning transitiometry method at 30 degreesC +/- 0.03 degreesC as a function of pressure and compared to the data found in the literature. The results are quite close to the literature values (4.2% at the very worst), and the uncertainty has been evaluated at 2%. A Tait equation, fitted from experimental density data, was also used to test the results of this work. The difference is between -5.9% and 3.2%.