CHEMICAL NOTATION AND ATOMIC WEIGHTS. 
583 
(C,H,)' HO 
(C,H,y Cl 
<W{ll8 
(<W { 
Cl 
Cl 
given radicle corresponds with the number of units lost or gained in passing 
from, or up to the corresponding saturated compound. 
C 3 II S represents a saturated compound; one, that is, which has no ten¬ 
dency to enter into combination with other bodies, and which can only un¬ 
dergo modification by means of substitution. Deprive it of II and we ob¬ 
tain a univalent group, C 3 H 7 , which forms an entire series of compounds. 
Let D 2 be subtracted, and a bivalent radicle is the result; whilst the removal 
of H 3 furnishes a residue which is trivalent. The following are examples of 
the mode of combination of these residues :— 
(HO 
(C 3 H 5 ) HO 
(ho 
(C l 
(C 8 H 6 )"' Cl 
(Cl 
Or take Hgl 2 which is in a state of saturation; take away I, which is equi¬ 
valent to H, and the residual Hgl constitutes a univalent radicle, which can 
form compounds like the following :— 
(Hgl)' I (Hgl)' Cl (Hgl)' Me 
Considerations like these explain the existence of the multitude of combi¬ 
nations with which organic chemistry is crowded. Organic chemistry is essen¬ 
tially the chemistry of the carbon compounds; carbon is an element whose 
combining capacity is multiple, and like others endowed with similar proper¬ 
ties it may exercise its faculties of combination upon four atoms of the same 
kind, or it may attach to itself four or fewer different radicles, either simple or 
compound, always providing that these supply units of affinity sufficient for its 
satisfaction. It has been seen in the instances already given how these ‘ mul¬ 
tivalent’ or ‘polyatomic’ elements and radicles are capable of condensing a 
great number of atoms into a single molecule. Others would show how this 
condensation might proceed, theoretical!} 7 ", to an unlimited extent; I shall 
content myself with the two following :— 
PO 
w 
PO 
III 
(HO* 
(ho 
O" 
(HO 
(HO 
etc. 
(C a H 4 )' 
(C 2 H 4 )" [ 
(C 2 H 4 )"{ 
(N II)" H+ 
(Nil)" 
(To he continued.) 
(NII)" 
(NH)" II 
etc. 
OBSERVATIONS ON THE MEDICINAL AND ECONOMIC VALUE 
OF THE OULACHAN {OS MET,US PACT FICUS, Rich.), A FISH 
BELONGING TO THE FAMILY SALMONIILE, FOUND ON 
THE NORTH-WEST COAST OF AMERICA. 
i 
BY ROBERT BROWN, F.R.G.S., 
FELLOW OV THE ROYAL PHYSICAL AND BOTANICAL SOCIETIES, FOREIGN MEMBER OF 
G. S. EDIN., CORR. MEMB. ACADEMY OF SCIENCES, SAN FRANCISCO, LATE COM¬ 
MANDER AND GOVERNMENT AGENT OF THE VANCOUVER EXPLORING EXPE¬ 
DITION, BOTANIST OF IRE BRITISH COLUMBIA EXPEDITION, ETC. ETC. ETC. 
The fish which forms the subject of this communication may, if we consider 
* Pyrophosplioric Acid. 
f Triethylone-tetramine. 
