410 Prof. De Morgan on Fernel's Measure of a Degree. 



give him an incli and a half more, he should have been as- 

 signed an inch and a half less. 



There is somewhere in Paucton, but I have not any note of 

 the place, a surmise that the geometrical pace was about 4|^ 

 Roman feet. This surmise seems to have arisen out of the 

 difficulty he found in otherwise reconciling the metrological 

 statements of the middle ages. A pace of 4| feet (Roman) 

 would have been 52 inches English, answering to Fernel's 

 geometrical pace. 



It is not necessary for me now to give the results of the 

 further inquiry which I made into the writings of the metrolo- 

 gists and cosmographers of the sixteenth century : I will merely 

 mention two things which struck me. George Agricola, 

 whose work on weights and measures was several times pub- 

 lished in the first half of the century in question, uses words 

 which seem to imply that measures absolutely derived from 

 the human body were in use in commerce, though his ex- 

 pressions are not conclusive : he is followed by several others. 

 Antonius Nebrissensis, whose work on Cosmography was pub- 

 lished at Paris in 1533, asserts that his own foot and his own 

 pace (he being, as he says, a man of moderate size) were the 

 measures actually used by geographers, and coincided with 

 the Roman measures. He mentions two places in Spain, the 

 distance of which was known in Roman miles from the Ro- 

 man itineraries, between which he had paced to ascertain this 

 point. So that Fernel seems to have used a less measure than 

 even the geographers of his time; and the difference can- 

 not be easily explained unless the supposition of Paucton be 

 adopted. It is hardly to be thought that Fernel laid down 

 an arbitrary measure for himself. His own words, that the 

 standard was to be selected " omni molimine," imply the con- 

 trary, for violimen means difficult endeavour. Neither, had the 

 measure been one of his own invention, would he have failed 

 to repeat the configuration in his Cosmotheoria. That he omitted 

 to do so was his " luck," and the misfortune of Picard, Cas- 

 sini, Montucla, Lalande, and Delambre, all of whom, as Mr. 

 Galloway truly states, took it for granted that he used the 

 Paris foot of his time ; to which I add, without, as far as ap- 

 pears, thinking it necessary to make a single inquiiy about 

 the usages of that time. 



The imagined good fortune of Fernel has acted unfavour- 

 ably upon opinion as to the measure of Norwood, which conies 

 also very near the truth, and was performed in a manner which 

 shows, that, like more modern observers, he laid himself out 

 for luck, by taking care to give every error equal chances of 

 being positive and negative. "With such a measure as that 



