C 221 ] 
XII. A Conjecture concerning the Method by which Car- 
dan’s Rules for refolving the Cubic Equation x z +qx-r 
in all cafes (or in all magnitudes of the known quan- 
Ferreus, of Bononia, or whoever elfe was the firjl In- 
ventor of them. By Francis Maferes, Efq. F. R. S. 
Curfitor Baron of the Exchequer. 
HERE is nothing more amufing, or more grateful 
to an inquifitive mind, in the ftudy of the fciences 
of Geometry and Algebra (for if we banifh from it the 
ridiculous myfteries ariling from the fuppofition of ne- 
gative quantities, or quantities lefs than nothing , the latter 
may deferve the name of a fcience as well as the former) 
than to contemplate the methods by which the feveral 
ingenious and furprizing truths that are delivered in the 
titles q and r) and the Cubic Equation x^—qx—r in the. 
Read January 27; 1780. 
ARTICLE I. 
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