SECTIONAL TRANSACTIONS.—B. 435 
13. Mr. W. G. Patmer.—Catalytic Actions in the System Copper, 
Copper-Oxide, Oxygen, and Gaseous Reducing Agent. 
The rate of oxidation of a copper film about ,,4;mm. in thickness can 
readily be found from observations on the increasing electrical resistance ; 
similarly the rate of reduction of oxide can be followed by observmg the 
decrease of resistance. Such a film conducts electricity normally, but is suffi- 
ciently thin for the effects of gaseous diffusion to be absent. 
Mixtures of reducing gas (such as carbon monoxide or hydrogen) with oxygen, 
when brought into contact with copper at 250° C., oxidise the metal more 
rapidly than does pure oxygen. This effect is very marked even when equal 
volumes of reducing gas and oxygen are used. The reduction of copper oxide 
by carbon monoxide or by hydrogen at low temperatures takes place only in 
the presence of copper, and the rate of reduction is simply proportional to the 
amount of metal present. 
When hydrogen is used for reduction the water formed acts as a ‘ negative’ 
catalyst, and the reduction is soon brought to a standstill unless the water is 
removed by exhaustion. Attempts to explain the effects described are greatly 
aided by the simplicity of the reactions concerned. 
14, Prof. W. Vrrnapsxy.—Alwmosilicates. 
We can distinguish in alumosilicates bodies of different chemical functions : 
anhydrides ; Al,SiO; sillimanite 
Al,Si,O, leverrierite 
Al,SiO,F, topaz, &e. 
acids; H,Al,Si,0; . H,O—kaolinite 
H,Al,SiyO;2—pyrophyllite, &c. 
salts : K,A1,Si,0;,— orthoclase, &c. 
All these bodies in the solid condition can give addition products, 
€.9. zoisite 3CaAl,Si,0; . Ca(OH). 
grossularite CaAl,Si,O, . CaySiO, 
where the alumosilicate group dominates the properties of the compound, 
the salts and their addition products can be divided into three groups : 
1. Sillimanite salts—of acid H,Al,SiO, and their addition products ; group of 
chloritoids. 
2. Leverrierite salts—of acids H,Al,Sic+,0.4+0n n=0, 2, 4, 6, 8. 
p.e. KoAl,Siy0s—phacellite 
K,AI,8i,0;.—leucite. 
The addition products correspond to general formula 
pA qB where A—alumosilicate 
B—group of elements of secondary importance. 
p=—1.2.3.... 
B22. 
These compounds have a chromogene constitution. 
All these compounds contain a nucleus M,AI,Si,O,, give by weathering clays 
(kaolinite H,Al,Si,0, . HO), and are obtained by natural and synthetical reactions 
from kaolinite. The common nucleus can be expressed in cyclic form : 
MO 
| 
Al 
MO 
Zeolites, felspars, nephelines, garnets, epidote, scapolites, &c., belong to this group. 
