REVIEWS — A TREATISE ON ANALYTICAL STATICS. 299 



chloro-compound, chlorocinnose. If I had regarded the essence as a hydride 

 C ,B H 14 03+H 2 , I should have named the chloro-compound chloride of chlorocinnise 

 C 18 H 5 C1 6 2 +C1 2 ; If I had considered the essence as a hydrate of cinnamyl 

 C I8 H'*0 + H 2 0, I should have called the chloro-compouad hydrate of chlorocinnose, 

 <tc, &c. 



Thus despite the similitude of the terminations, despite the same valuta ascribed 

 to the same vowels by Dumas and myself, there is not any analogy between the 

 ideas which these two nomenclatures represent, excepting, that they both express 

 the quantity of hydrogen set free, and the quantity of chlorine fixed. 



I will adduce the following examples, to show the absolute difference that exists 

 between my opinion and that of Dumas. 



Dumas represented alcohol by C + H 8 + H 4 0-, and acetic acid by C*H 6 3 +H a O 

 and nevertheless saw a case of substitution in the conversion of the first into the 

 6econd : 



Alcohol — 2H 2J -20=acetic acid. 



Since at that time, Dumas maintained that alcohol contained 2 atoms of water, 

 while acetic acid contained only one, it is ckar that in his law of substitutions, he 

 considered only the ratio between the hydrogen liberated, and the chlorine or oxygen 

 fixed, without pretending that the primitive and the derived body, belonged to the 

 tame type. 



This is rendered still more evident by the following example?, which Dumas 

 brought forward in support of his law : 



Alcohol — 4 H2 + 40=formic acid, 

 Acetic acid —2 H?+20= " " 



It is certain that Dumas, notwithstanding the equivalent substitution, did not 

 consider alcohol, acetic acid, and formic acid, as belonging to the same type- 

 It was some considerable tioie after thU, when he had discovered the chioracetic 

 acid, that ha adopted my opinion concerning the functions of chlorine in substitu- 

 tion compounds, which view he extended so as include oxygen, although I had my- 

 self ceased to apply it to this last b 



We strongly recommend this valuable work to the attentive perusal 

 of si. higher departments of theoretical chemistry. 



H. C. 



A Treatise on Analytical Statics, with numerous examples. By J. 

 Todhunter, M- A., Follow and Assistant Tutor of St. John's Col- 

 lege, Cambridge. Cambridge : Maemillan & Co., 1853. 

 In a review of Mr. Todhunter' s Analytical Statics, which appear- 

 ed in a late number of the. Canadian Journal, * we pointed out what 

 appeared to us a fallacy in Poisson's proof of the Parallelogram of 

 Forces. Since that review was written we have discovered that the 

 defect lies in a much smaller compass, and may be remedied in much 

 fewer words, than v/e at first imagined : though Poisson's own word- 

 ing certainly leaves hi.s reasoning open to the objection laid against it. 

 We may remind our readers, that Poisson, in the first place, shews 



* Inte, Reviews, No. 1, p. C">. 



