PALPABLE MATHEMBTICS. 189 



X. 



Palpable Mathematics ; or Methods of writing and calculating 

 for the Ufe of the Blind. By J. B. Berard. * 



V^ITIZEN Haiiy having compared the methods of writing Citizen Hauy's 

 and calculating of feveral celebrated blind men, has digefted jj£ "JjJjJ £ 

 into a body of doctrine the beft productions of experience in writing, &c. 

 this art. He has compofed a fyftem of inftruction, and has 

 defcribed the instruments proper to be ufed in this operation : 

 and he truly deferves well of humanity, who increafes the means 

 of communication between fogiety, and a clafs of men who 

 feem to have been excluded from it, and to have been con- 

 demned to lead an unhappy life, ufelefs to others, and with- 

 out enjoyment to themfelves. 



Having been my felf deprived of fight fince the age of twenty- The author ia 

 three, meditation and experience have given me the unhappy Win< *» 

 right of treating upon the art concerning which he has written. 

 I here give fome obfervations which may not be entirely ufe- 

 lefs to fociety. 



ARITHMETIC. 



The method by which the celebrated Saunderfon calculated Profeflor Saun- 

 is well known; however ingenious it may be, it does not " on s n ? etho<i 

 feem to me to be the beft ; I obferve two principal defects in 

 it. 



He ufed fmall fquare pieces with nine holes in each : the by fquares to de- 

 the pofition of a pin in one of thefe holes denoted one of the notethe di 2 its » 

 nine figures. It is therefore neceflary to have as many of 

 thefe fquares as the operation requires of figures or characters : 

 and we mull employ an extended fpace for a very ample cal- 

 culation. 



In the fecond place, this method of calculating being en- required a great 



tirely different from that of perfons who can fee, they cannot J? 3 ."* and jj not 

 J jf lit legible to others. 



underftand the particulars of it; this is a confiderable mcon- 



Ivenience, becaufe it deftroys all connection between the blind 

 and thofe who operate by fight. 

 The method which appears to me the beft, confifts in em-It is better to 

 ploying characters reprefenting figures, and arranging them c °™ p ° fe f 

 nearly as they are compofed in printing. 

 * Melanges Phyfico Mathematiques. 

 ALGEBRA. 

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