Page:Eleanor Gamble - The Applicability of Weber's Law to Smell.pdf/48

44 rubber, and the musk-root is five times stronger than the former. The tallow, Zwaardemaker says, is stronger still. We regret that we could not find stimulus-limina oftener. The washing of the tube consumed 80 much time that this was impossible. We feel that the results embodied in Table I are the most unsatisfactory part of our work, yet if allowances be made for exhaustion in some of the results of C. and Sk. and for expectation gradually controlled by practice in the cases of Bi., M. and Rog., the Table will serve its purpose.

We have not space to give our temperature records in full. They varied so irregularly that the arithmetical mean by no means represents the most common reading. As the steam had to be kept shut off when we were not in the laboratory, the exact regulation of the temperature involved serious practical difficulties, and for most of our work it was a matter of minor importance, for in difference-determinations variations of temperature and moisture affect the standard-stimulus and the stimulus of comparison equally, and may, therefore, be disregarded. Indeed, our barometer-records, though carefully kept, proved to be wholly a work of supererogation, for in the case of the very few substances (glycerine soap, coumarine, heliotropine, vanilline, and allyl sulphide) which were somewhat soluble in water and yet not in aqueous solution, we did not succeed in finding stimu1us-limina on different days. Practice lowered the stimulus-limina in a conspicuous manner, but the effect of variations in temperature can only occasionally be traced in the complete results. Part 2 of Table I illustrates this fact with fairness.

It only remains to say that Be., C., K., N., Se. and T. worked twice a week for at least part of the year and the others once.

Section 2. Results Obtained by the Method of Just Noticeable Differences.

Since in the nature of the case numerical proof of the applicability of Weber's Jaw to a given sense department cannot be thrown into the form of averages, and since we have not space for the great mass of figures which we have at hand, we must offer first samples and then summaries of our evidence, and content ourselves with them. Tables II and III are the samples, and Tables IV, V and VI are summaries from different points of view. Table V constitutes the most decisive proof of the validity of the law. Tables V and VI are intended to confirm the conclusion to be drawn from Table IV, and to show the probable value of $Δr/r$. In Tables III, IV, V and VI, every value given or enumerated is an average of the results of one day’s work with one subject, nostril, substance and standard. All the work done with this method, however unsatisfactory, is represented in Tables V and VI.