Although encouraging progress has been made in the measurement of loudness, certain objections to the sone scale have been raised from time to time. This paper tries to answer some of these objections, and especially to show how the form of the sone scale can be verified by cross‐modality matchings. Instead of working with numerical estimations of magnitudes or ratios, these new procedures allow observers to equate the apparent intensity of stimuli in two different sense modalities. It turns out that the results of these cross‐modality matches can be predicted from the relation between the sone scale and the subjective scales in the other modalities. These experiments strengthen the evidence for the validity of the sone scale. They also suggest that the form of the subjective intensity function depends on the “input‐output” operating characteristic of the sensory system and not on some prior experience which the observer may have had with a “physical correlate” of the stimulus.