Compressions of liquids. II. Critical evaluation of new n ‐alkane data: n ‐Heptane to n ‐tetracontane

New measurements of the volumes of liquid n ‐alkanes of 7, 9, 11, 13, 17, 20, 30, and 40 carbon atoms over a range of temperatures from 20° to 300°C. and pressures from 0 to 4,000 kg./sq. cm. have been made. These volume measurements are here reduced to compressions ( vol   p T )/( vol° T ), and the accuracy of the measurements has been determined. Analysis of the data for n ‐heptane and n ‐eicosane shows that the order of accuracy of the compressions of each of these compounds appears to be approximately 3 parts in 10,000. Evaluation of random multiple measurements on the remaining six compounds indicates that their over‐all accuracy is likewise of this same order.