182 
METHYLATED HUM. 
IIC1 
HClO'o 
HC10' 4 
HC10' 6 
HClO'g 
HC1 
Chlorhydric acid. 
HCIO" 
Hypochlorous acid. 
HC10" 2 
Chlorous acid. 
HCIO'C 
HC10" 4 
Chloric acid. 
Perchloric acid. 
C 4 KH 5 0' s 
C 4 KH 5 O' 10 
c 4 kh 5 0' 12 
C 4 KH 6 O f, 4 
c 4 kh 5 0" 5 
C 4 KH 5 0" fi 
Acid succinate. 
Acid malate. 
Acid tartrate. 
Throughout there is no difference of 8 parts of oxygen, or of any odd multiple of 8 
parts of oxygen, between the successive compounds. 
It follows also that whenever oxygen, with or without some other element, is added 
to or taken from a compound, the oxygen so added or eliminated must always be repre¬ 
sented by 16, or some multiple of 16 parts, as instanced in the following decompositions, 
representing the liberation of oxygen from nitrate, permanganate, and chlorate of potas¬ 
sium respectively.— 
KN0 3 = KNOo 
2H„S0 4 + KMm0 4 = 2H„0 + KMm(S0 4 ) 2 
KClOg = KC1 
+ 
0" 
or 
O', 
+ 
0" 2 
or 
0' 4 
+ 
0". 
or 
0'« 
Let the decompositions be expressed how they may, the oxygen displaced cannot ap¬ 
pear as 8 parts, or any odd multiple of 8 parts ; and so in hundreds of other instances. 
The representation of the molecule of water by the formula H 2 0 was proposed by 
Gay-Lussac, advocated by Berzelius, and employed by Davy more than fifty years ago. 
Its revival is due to Gerhardt, who in conjunction with Laurent made it the basis of a 
consistent system of chemistry, since brought to a higher state of development by the 
labours of many distinguished chemists, including more especially Professor Williamson, 
who first introduced it into this country and supported it by a series of most masterly 
researches. 
In accordance with this system, four well-defined classes of primary hydrides are re¬ 
cognized, the leading member of each of which constitutes the type or model to which 
an infinite variety of compounds are referable as regards both their composition and be¬ 
haviour ; thus:— 
Monhydrides. 
HF 
HC1 
HBr 
HI 
Dihydrides. 
H 2 0 
h 2 s 
HnSe 
ILT 
Trihydrides. 
H 3 N 
h'p 
H 3 As 
H 3 Sb 
Tetrahydrides. 
h 4 c 
H 4 Si 
Formulated as above, all these hydrides occupy the same volume, and their respective 
vapour-densities compared with that of hydrogen as unity are the halves of their atomic 
weights. 
METHYLATED RUM. 
The following Act was passed last Session in order that rum, when methylated under 
the conditions specified, might be used as a desiccant for paint in place of spirit of 
turpentine:—• 
Cap. CII.— An Act to Reduce the Duty on Rum in Certain Cases. 
Whereas by an Act passed in the eighteenth and nineteenth years of her Majesty’s 
reign, chapter thirty-eight, spirit of wine is allowed to be methylated duty-free, and it 
is expedient to allow foreign and colonial rum to be also methylated on payment of the 
reduced duty hereinafter mentioned: be it enacted by the Queen’s most Excellent Ma¬ 
jesty, by and with the advice and consent of the Lords spiritual and temporal and 
Commons, in this present Parliament assembled, and by the authority of the same, as 
follows:— 
1. It shall be lawful for the Commissioners of Customs to permit and authorize any 
licensed rectifier of spirits, or any person who shall be duly licensed under the said re- 
