58 REPORT—1858. 
Carbon...=5 +1 6= ab+b corresponding to 
Boron ...=5,4+1 = 11=2ab+6 As Methyle. 
Silicon... =5,+1 = 21=4ab+6b “s Ethyle. 
Zircon ...=5,+ l= 31=4ab+b 4 Propyle. 
The following family was also included in Mr. Mercer's calculations :— 
Fluorine =5+N = 19 
Chlorine =5+P = 36 
Bromine =5+As= 81 
Jodine =5+S85=126 
From the tables exhibiting the possible construction of elements, the following 
may be taken as an example, introducing as it does two other families :— 
4, = O. 
4; = —— Mg. 
4, = Ss. 
a = Ca. 
Ai) = Se. 
4 = -—— Sr. 
re Te. 
47 — Ba. 
4 4+3= L. 
4,+3= —— Na. 
4,+3= K. 
It will be observed that each member of the magnesium group is 4 in advance of 
the corresponding member of the oxygen group. 
On the Atom of Tin. By Dr. W. Ovtine, F.C.S. 
The author argued, from both original and recorded experiments, that the atomic 
weight of tin was not 59, as usually accepted, but the double thereof, or 118; and, 
consequently, that stannous salts were not protosalts, but bisalts; and stannic salts 
not bisalts, but quadrisalts. This view was supported by the following considerations ; 
namely, that stannous oxide has the property of expelling carbonic acid from fused 
alkaline carbonates ; that stannous oxide does not form any combination with carbonic 
acid; that stannous salts are completely decomposed by chalk and insoluble carbon- 
ates, even at ordinary temperatures; that stannous chloride is readily fusible and 
volatile, and is decomposed to a considerable extent by water; that stan-ethyl, or 
stannous ethyl, has not the properties of a prot-ethylide, but of a per-ethylide, as in- 
stanced by the facility with which it combines with oxygen and chlorine, and replaces 
the basic hydrogen of different acids; that the vapour-density of stannic chloride 
requires the existence of four atoms of chlorine in its molecule; and, lastly, that 
stannic fluoride corresponds closely to silicic fluoride, the molecule of which, as shown 
by its vapour-density, contains four atoms of fluorine. 
On the Purple Dye obtained from Coal-Tar. By W. H. Perkin, P.CS. 
This dye, a specimen of which was exhibited, is a product of the oxidation of ani- 
line by bichromate of potash. It is a bronze-coloured substance, dissolving in alcohol 
with a beautiful purple colour. It is difficultly soluble in water, but more soluble 
in acidulated water. Like indigo, it is perfectly decolorized by the hydrated prot- 
oxide of iron, the colour being restored again by exposure to the air. It dissolves in 
concentrated sulphuric acid, forming a green solution, which, upon the addition of 
water, precipitates the colour unchanged. It is not affected by digestion with an 
alcoholic solution of potash. It decomposes slowly at 250°C. _ It is applicable for 
dyeing and printing silk, cotton, or wool. Its colour is exceedingly intense, one 
pound of the solid substance dyeing no less than 200 lbs. of cotton a moderately dark 
lilac. The colours thus produced are very permanent, standing the action of light 
and heat, acids and alkalies, Samples of silk dyed with it were exhibited. 
