992 REPORT— 1885. 
It therefore occurred to me, that by directly attaching an electro-motor to the 
revolving drum or basket (or table as in Mohr’s instrument), the inconvenience 
attending the driving might be got over, and at the same time a combination of 
great efliciency would result, as the electro-motor like the centrifugal machine is 
most efficient when driven at a high speed. 
‘The apparatus consists essentially of a basket or drum of perforated copper 
(it might be of iron, or other suitable metal, or of ebonite) slipped on to a cone 
attached to the spindle of a small electro-motor, and is held in position by means 
of anut. The surrounding casing serves to catch the liquid driven out of the 
substance being dried. The electro-motor consists of a Siemens H armature, which 
revolves between the poles of an electro-magnet of soft iron. The centrifugal 
machine, as is well known, has many industrial applications. It is used in laundries 
and in the textile manufactures for drying wool and cloth, in dyeworks for drying 
feathers, and in the manufacture and refining of sugar, for the separation of the 
sugar crystals from the syrup, but it is only quite recently that chemical manu- 
facturers have awakened to its value. 
2. Barium Sulphate as a Cementing Material in Sandstone. 
By Professor Frank Crowes, D.Sc.—-See Section C, p. 1038. 
3. An Apparatus for determining the Viscosity of Oils. 
By A. H. Auten, F.C.8. 
4. The Action of Nitrous Gases upon Amyl Alcohol. 
By J. Wituams, F.0.8., F.L.C., and Mytes H. Sira, F.C.8. 
Having had occasion lately in the manufacture of amyl nitrite, to determine 
for commercial and manufacturing purposes the best mode of producing the 
largest possible result from a given amount of materials, the following results 
were obtained. 
We should mention that in all the trials the same sample of amyl alcohol was 
employed. This had been well purified by washing, fractional distillation, and 
several distillations in the vapour of steam; it was therefore practically nearly 
pure, but may still have contained traces of ethylic and butylic alcohols, and per- 
haps other bodies, 
The nitrous gases were produced by the action of nitric acid of various 
strengths upon arsenious acid. With the very strong acids it was necessary that 
the arsenious acid should be in lump to moderate the action. 
It was found that the gas produced by nitric acid of sp. gr. 1500 was 
nearly entirely absorbed by the amyl alcohol, which when completely nitrified 
changed in colour from a bright yellow to a greenish-brown., The product, washed 
and distilled, gave only from 42 to 48 parts distillmg under 100° C., about 85 
parts under 120°, and remainder boiling at a considerably higher point. This 
result was very unsatisfactory, and proved that the gas produced by acid of this 
strength was nearly pure nitrogen tetroxide, which in contact with the amyl 
alcohol was split up into nitrous acid (producing less than one-half nitrite amyl) 
and nitric acid, producing higher products of oxidation. 
Nitric acid of 1420 was then tried, Much of the gas was absorbed, but a con- 
siderable quantity of unabsorbable gas was produced, and the product yielded about 
65 to 70 parts of a distillate coming over at 100° or a little above. This result, 
although better, was not at all satisfactory. 
Nitric acid of 1850 gave a gas which contained a still larger proportion of 
unabsorbable gas, but ultimately yielded a product which gave on one occasion 
as much as 90 per cent. of distillate under 100°, and 95 under 105°. 
When nitric acid of sp. gr. 1300 was employed, most of the gas obtained 
was unabsorbable, but a small percentage of absorbable gas was obtained, which 
