CHEMICAL NOTATION A'SD ATOMIC WEIGHTS. 
527 
When water is treated with metallic potassium, hydrogen gas is evolved and 
caustic potash formed ; this caustic potash has been usually expressed sym¬ 
bolically KO,HO ( — KH0 2 ) ; that is, from two equivalents of water, 
2 HO, Half of the hydrogen has been expelled, and potassium substituted for 
it. Again, if caustic potash be fused with metallic potassium, the remainder 
of the hydrogen is driven out, and we obtain oxide of potassium, KO or 
K 2 0 2 . The hydrogen is then replaceable in two stages. 
By a well-known series of reactions, alcohol, ether, and the double 
others may be produced from water. By acting upon water with potassium, 
caustic potash is formed w r ith evolution of hydrogen ; caustic potash digested 
with hydriodic ether furnishes alcohol and iodide of potassium ; potassium 
immersed in alcohol evolves hydrogen, and gives rise to a compound called 
potassium-alcohol; hydriodic ether made to act on potassium-alcohol pro¬ 
duces ether and iodide of potassium ; lastly, if methyl-hydriodic ether be 
substituted for iodide of ethyl, a compound results which is called a double 
ether, since it contains both methyl and ethyl. In symbols, all these reac¬ 
tions would be expressed as follows :— 
2 HO + K = H + KH0 2 
khOo + k = h + k 2 o; 
EH0 2 + EtI = EtH0 2 + KI 
EtH0 2 + K = EtKO, + H 
EtKO., + EtI = Et„0„“-f- KI 
EtK0 2 + Mel = EtMeO., + KI 
This last substance, it is important to observe, possesses all the characteris¬ 
tics of a true chemical compound; it is no mere mixture of ethylic and me- 
thylic ethers. Its formula, therefore, can in no way be reduced or simplified ; 
it consists of the two organic radicles methyl and ethyl united to 16 parts by 
weight of oxygen (2 equivalents), that is, to the same quantity that obviously 
exists in common ether, in the alcohol from which it was formed, in caustic 
potash, and in 2 equivalents of water. 
Oxygen = 8. 
Water .... 
Potash .... 
Oxide of Potassium 
Alcohol .... 
Potassium-alcohol 
Ether .... 
Methyl-ethyl-ether 
Ethyl-amy 1-ether 
H 2 0 2 . 
hko 2 
k 2 o 2 . 
EtHO, 
EtK0 2 “ 
Et 2 0 2 . 
MeEt0 2 
Et AmO., 
Oxygen = 16. 
. h 2 o 
. HKO 
. K 2 0 
. EtHO 
. EtKO 
. Et 2 0 
. MeEtO 
. EtAmO 
If it be admitted then that the oxygen of ether is one chemical atom (that is, 
according to the definition, an indivisible quantity), that of water must be so 
likewise, and its molecule must be assumed equal to 18. 
If a series of oxides be examined, it will be found in all cases that each 
term of the series differs from those which precede and follow it by a quan¬ 
tity of oxygen, which is an even multiple of 8 parts by w r eight, never an odd 
multiple of that number. 
Hydrochloric Acid 
Hypochlorous Acid 
Chlorous Acid . . 
Chloric Acid . . 
Perchloric Acid . 
Oxygen =8. Oxygen = 16. 
. HC1 . . . HC1 
. HC10 2 . . HCIO 
. HCIO, . ; HC10 2 
. HC10 6 . . HC10 3 
. HC10 S . . HC10 4 
