268 Mr. William Sutherland on the 



simplicity at first, I ignored the fact that two of the paraffins in 

 Schiff's data are iso-compounds.) 



From the tabulated values for the alkyl salts of the fatty 

 acids, we get I he following mean values for the dynic equi- 

 valent of CO"0' : — in the formiates 1*85, acetates 1*92, pro- 

 pionates 1*91, butyrates 1*92, isobutyrates 1*91, and iso- 

 valerates 1'83, the mean for all being 1*9. 



From the oxides (ethers) and other compounds containing 

 single-bound 0, we find for its mean value *6, although in the 

 ethers containing the benzene nucleus it comes out *8, while in 

 the benzoates CO^O' is about 2 # 5 ; so that the junction of the 

 benzene nucleus with other groups seems to be accompanied 

 with an increase in its value : witness also the bromide, iodide, 

 and amine of C 6 H 5 , equal to the bromide, iodide, and amine of 

 C 5 H n , although C 6 H 6 is less than C 5 H 12 by *25. This slight 

 variation of the value of C 6 H 6 is the only anomaly amongst the 

 numbers of Table XXV. excepting the simple typical com- 

 pounds. The values *6 for 0' and 1*9 for C"0' are in harmony 

 with the results for all the other compounds containing oxygen. 



From the values for the benzene series of hydrocarbons we 

 can get a value for H 2 in CH 2 , and also some light on the 

 important question of the structure of the benzene nucleus. 

 Thomsen has been led by his thermochemical investigations to 

 the conclusion that in benzene each carbon atom is bound 

 to three other carbon atoms by a single bond to each (the 

 " bond " phraseology is used merely for brevity, and not as 

 expressing definite statical or dynamical facts). If we accept 

 this conclusion, then the dynic equivalent of 6 H 12 minus that 

 for C 6 H 6 is equal to the dynic equivalent of 3H 2 ; similarly, 

 from the other members of the benzene series w T e get the values 

 for 3H 2 , the mean result being 1'29 or '43 for H 2 . 



The accepted structure for C 6 H 10 diallyl is (OH 2 CHCH 2 ) 2 , 

 or four whole CH 2 groups and two CH 2 groups with H removed 

 from each ; and as the dynic equivalent of C 6 H 10 is 5 6, we find 

 that of H 2 to be "4. Again, recent investigations on the ter- 

 penes ( Wallach, Ann. der Chem. ccxxv., ccxxvii.. ccxxx. ; Bruhl, 

 ccxxxv.) show that the two ordinary forms can have their for- 

 mulae written CH 3 C 3 H 7 (CH 2 ) 2 (CH) 2 C 2 ; that is to say, they 

 have 6 hydrogen atoms cut out of CH 2 groups, and as the dynic 

 equivalent of C 10 H 16 is 9 we have that of 3H 3 as 1/0 or that 

 of H 2 -33. Since the value *43 is derived from 10 accordant 

 members of the benzene series, we will take it as the value of 

 the dynic equivalent of H 2 in CH 2 . 



By similar but simpler reasoning the dynic equivalents of 

 CI, Br, I, and other radicals are easily found, and the 

 following is a list of mean values : — 



