218 



writers on logic have fallen into this vague use of the word, and 

 though it was so understood in the disputations of the Cambridge 

 schools. The proper use of the word '•argument" in logic is to 

 denote " the middle term," i. e. " the term used for proof." In a 

 sense similar to this the word is employed by mathematicians ; and 

 there can be no doubt that the oldest and best logicians confine the 

 word to this, which is still its most common signification. 



The author entered at some length into the Aristotelian definition 

 of the enthymeme, which may be rendered approximately by the word 

 "argument." He also explained how the words "topic" and 

 " argument " came to denote the subject of a discourse or even of a 

 picture. He showed, by a collection of examples from the best 

 English poets, that the established meanings of the word " argu- 

 ment" are reducible to three: (1) a proof or means of proving; 



(2) a process of reasoning or controversy made up of such proofs ; 



(3) the subject matter of any discourse, writing, or picture. And he 

 maintained that the second of these meanings ought to be excluded 

 from scientific language. 



December 12, 1859. 



The following paper from the Astronomer Royal was read : — " Sup- 

 plement to the proof of the Theorem that ' Every Algebraic Equa- 

 tion has a Root.' " 



The author expressed his want of confidence in every result ob- 

 tained by the use of imaginary symbols, and in this supplement 

 demonstrated that the left-hand member of every algebraic equation 

 of the form <j> (#) = admitted of resolution, either into real linear 

 factors, or into real quadratic factors. 



Professor Miller also made a communication " On a new portable 

 form of Heliotrope, and on the employment of Camera Lucida prisms 

 and right-angled prisms in surveying." 



February 13, 1860. 



The Rev. H. A. J. Munro read a paper " On the Metre of an 

 Inscription copied by Mr. Blakesley, and printed by him in his 

 ' Four Months in Algeria,' p. 285." 



February 27, 1860. 



The Rev. Professor Sedgwick made the following communica- 

 tions : — 



1 . "An account of Mr. Barrett's progress in the Survey of Jamaica, 

 with some remarks on the Distribution of Gold Veins." 



