For some years after the apôÙpearôÙance of MoseôÙley〙s paper, a number of writers followed in his footôÙsteps, and atôÙtempôÙted, in various ways, to put his conôÙclusôÙions to pracôÙtical use. For inôÙstance, D〙OrôÙbigôÙny deôÙvised a very simôÙple proôÙtracôÙtor, which he called a HelôÙiôÙcoôÙmeterÿ£¢18, and which is repôÙreôÙsented in Fig. 267. By means of this litôÙtle inôÙstruôÙment, the apical angle of the turôÙbiôÙnate shell was imôÙmeôÙdiateôÙly read off, and could then be used as a speôÙciôÙfic and diagôÙnosôÙtic charôÙacter. By keepôÙing one limb of the