478 Scien tific In telligence . [ D e^ . 



* . 

 k S + 3 Al S + 24 H. The latter has the advantage in distinct- 

 ness, as well as brevity j the sign + being interposed between the 

 compounds of the second order (or those and water) not between the 

 combinations of acid and base ; whilst the common negative element 

 is placed in circumstances of particular facility of computation, where 

 the eye perceives its proportions, in the different ingredients, with 

 hardly an effort of the mind. The law to which this last commenda- 

 tion applies, Professor Thomson has been at some pains to invalidate ; 

 but as it holds good in salts containing bases of (M2 O^) as well as 

 of M (M O) and in the sulpha-salts, and compounds of chlorine, &Co 

 as well as in the oxy-salts, it seems fairly entitled to the character of 

 a general law, notwithstanding a few exceptions. 



" A little more care, on the part of the printer, the points may 

 require, thus applied out of their usual place and signification. But 

 if this objection is intended to hold further than with the printer, it 

 is anticipated by the mathematicians, in the alternative of the letters 

 and exponents. K O they say, signifies K multiplied into O ; and 

 S 03, S multiplied into O cube; and they ought not to be used by 

 chemists in any other sense . They have, however, already practi- 

 cally repelled, not only your objections, by using the point equally 

 out of place, as a fluxivoal sign : but their own, by continually 

 employing the alphabetic characters, both italic and Greek, without 

 regard to their proper signification. It remains to be shown why 

 the chemist should be more restricted. 



" These are the chief reasons that occur to the writer for the use 

 of symbols, and of the particular ones in question. It is needless to 

 fill your pages with anticipations of objections which may be better 

 answered if they arise. P." 



2. Mr. Hiley urges the mathematical objection against the use of 

 S 03 preferring S -f 3 O (the type of the numeral exceeding in size 

 those of the symbols of the elements), and recommending the inter- 

 position of the positive sign in all cases, as Ba + O for Barytes, and 

 (Ba + O) -f (C -F 2 0)for carbonate of barytes; N + 50for 

 nitric acid ; 2 Cu + CI, for dichloride of copper, &c. ; or to those 

 who " would prefer sacrificing explicitness to brevity," the symbol 

 (Ba -f C) for carbonate of barytes, might be more acceptable. With 

 regard to points and commas, his " decided opinion is, that they ought 

 to be laid aside." They bear no similarity, he continues, " to the 

 other symbolical expressions with which we are acquainted. They 

 are like nothing in algebra or other parts of mathematics, or at all 

 events, wherever signs of this nature have been used, their applica- 

 tion is entirely different, and moreover, their positions vary. The 

 dot when employed in algebra, is placed alongside the symbol, as a. 

 b. c, and indicates multiplication. Whereas, when chemically ap- 

 plied, its situation is over the symbol, and is indicative of addition. 

 As in algebra the vinculum in the shape of a parenthesis is preferred 

 to the long line drawn over each of the compound factors : so in the 

 case of symbols, initial letters and figures are more eligible than points 

 and commas." 



* This symbol for alumina accords with Thomson's atomic system, not that of 

 Berzelius. 1 do not t-ive it as the true one. 



