J. H. Gore — Decimal System of Seventeenth Century. 23 



This scheme derived its unit from a minute of the arc of the 

 largest circle that can be drawn around the world. A minute 

 of arc was called a milliare y one-tenth of a milliare was to be 

 called a stadium y one-tenth of a stadium, a funiculus y one- 

 tenth of a funiculus, a virga y one-tenth of a virga, a virgula y 

 one-tenth of a virgula, a digitus y one-tenth of a digitus, a 

 granum y one-tenth of a granum, a jpunctum y as is con- 

 veniently exhibited in the following diagram : 



If the above terms appear inconvenient to any one, the fol- 

 lowing were given so that one could take one's choice : Mil- 

 liare, centuria, decuria, virga, virgula, decima, centesima, mil- 

 lesima, If we now take the accepted value for the quadrant 

 in English measure, the various units will have these lengths 

 in inches : 



Milliare _„_ 72908- 



Centuria 7290-8 



Decuria 729-08 



Virga. 72-908 



Virgula 7*2908 



Decima ...-7290 



Centesima -0729 



Millesima -0072 



There were to be two units, the virga for large measures, 

 and virgula for shorter ones— the former, about six feet, is 

 most convenient for measuring those distances now expressed 

 in yards, or meters, while the latter would be suited to those 

 quantities now expressed as fractional parts of a foot, or feet. 

 Those who use the metric system find that the meter is rather 

 long for the latter class of quantities, nor is it convenient to 

 use decimeter, and the jump to centimeter is too great, while 

 for the first named measures the meter is too short. If these 

 views be correct, Mo u ton's duplex units virga, and virgula are 

 preferable to the meter. 



Just when this scheme was proposed is not known, but it was 

 prior to 1665, as some observations in connection with the fixing 

 of his standards were made on the 8th of March of that year. 

 Geodesy had not reached at this time a stage where its results 

 could suggest their application to metrology ; in fact only two 

 determinations of the length of terrestrial degrees had been 

 made, those of Snell and Riccioli, in 1617 and 1665 respec- 

 tively. Not enough was then known of methods to enable 

 one to judge as to the accuracy of either of these determina- 

 tions, but Mouton says : Of all the observations I know of, 

 ancient as well as modern, those of John Baptist Eiccioli, which 

 are described in the fifth geometrical book of the revised 

 geography please me most, both on account of their wonderful 

 harmony and the singular diligence which the above-mentioned 



