1 882. 55 Trans. N. V. Ac. Set, 



ing the results of quantitative work and has suggested the use of 

 them to his students. When, for instance, the word "crucible" 

 must be repeate 31y entered upon a record, it is very convenient to 

 indicate it by a cross (x) (the object from which it is derived), or 

 by a cross within a triangle, a cross within a circle, or, if preferred, 

 by the abbreviation "xble " all of which were used by the alchem- 

 ists. Again the letter V may conveniently be used as an abbrevia- 

 tion of the word precipitate, and the same symbol, inverted thus ^, 

 may be applied to indicate a gas. 



As an illustration of the use of symbols in this way take the fol- 

 lowing common form of record of an analytical operation : 



Weight of the crucible and cover containing the 



precipitate and ash 26.4573 



" " crucible and cover alone 26.1729 



Weight of the precipitate and ash 2844 



" " ash 0010 



" " precipitate=Alo03 2834 



and note how much more conveniently it may be represented by 

 symbols as follows : 



W, X -I- c + V + *E 26.4573 



W, X + c only 26.1729 



W, V, + *E 2844 



W, *E 0010 



W, V=Al203 2834 



The signs he has personally used were adopted with no especial 

 respect to conventionality, but in " Hall's Encyclopoedia," a book 

 published in 181 2, he lately met with a table of " Chymical, &c., 

 Characters, " which was engraved in 1793, and he found that many 

 of them were identical with those he was using. So he has inserted 

 on the inside cover of his Laboratory note book, a photographic 

 copy of the table which seems quite complete, and such of its sym- 

 bols as are appropriate he applies to a practical use.* 



