R A I 



of Wedgwood's and the freezing point of mercury a little below 8|, and 

 that there are 80 from the freezing of water to full ignition. 



Q 



QU ADRATRIX of Dinostrates, Equation to. 



y V 7-2 $2 s ( r _ A ^ } where r = radius, and s the sine of the circ. 

 arc, by the help of which the curve is generated. 



The radius of the generating circle is a mean proportional between the 

 quadrantal arc and the base of the quadratrix. 



If with the base of the quadratrix as radius, there be described a qua- 

 drantal arc, this will be equal in length to the radius of the generating 

 circle. 



QUADRATURE of Curves. See Area. 



R 



RADIUS vector of a planet's orbit. See Anomaly. 

 RAIN, quantity of at different places. 



Mean annual quantity of rain for 30 years, as observed at the apartment* 

 of the Royal Society. The gage is placed 75 feet 6 incJies above the 

 ground. 



YEARS. 

 1790 

 1791 

 1792 

 1793 



1794 



1795 



1796 



1797 



179S 



f '99 vw^rw^yvy^^ 



