94 
POPULAR SCIENCE REVIEW. 
the animal was of greater height than. Rhinoceros or Acerotherium. The 
teeth consist of the last upper molar and several lower molars ; the upper, 
being larger and narrower than that of Rhinoceros. Its external face is 
slightly convex, and the hollowing of its crown is narrow and elongated. 
The lower molars are smaller than in Rhinoceros , with collines much more 
oblique and less projecting; their external face is undivided, and has but 
a slight curvature. The porcine remains from these beds consist of 
Anthrcicotherium , Anoplotherium , Entelodon , Hyotlierium , Cciinotherium , 
and a small animal allied to the .latter, which possesses a well-marked bar 
between the first and second false upper molars. The ruminants consist 
of Amphitragulus and a species of Cervus. There are many species of 
Hyenodon , also Cricetodon and Archceomys, whilst Peratherium , Axes, 
terrestrial Chelonicins, a species of Crocodile , Locertians , and Serpents are all 
represented. 
MECHANICS. 
The Sand-blast Process. — One of the most interesting novelties in the 
mechanical world of late has been this process, which is of American origin, 
and which seems to pound the glass rather than to cut it. Eor curious 
polanscopic observations have been made, we fancy, by Mr. F. Wenham, 
V.P.R.M.S., on the subject. The main object of the inventor of this process 
was to engrave ornamental and other devices upon plain and coloured glass, 
upon stone, and upon metallic surfaces, in an expeditious and economical 
manner, and with a sharpness which is unattainable by any other means. 
The invention, which applies chiefly to intaglio and flat relief engraving, is 
based on the fact that when glass, stone, or metal is subjected to the impact 
of a blast of sand, or equivalent hard granular substance, the detrition of the 
surface exposed to its action will be rapidly effected. Although the sand- 
blast acts with energy upon hard or brittle surfaces, it has little or no effect 
upon elastic and soft substances, such as india-rubber, wax, paper, and lace, 
and it is upon such substances, therefore, that the patentee relies for pro- 
tecting those parts of the glass, stone, wood, or metal which are intended to 
be untouched by the sand-blast. Thus, a piece of lace spread over and 
cemented to a sheet of glass will so effectually protect" the glass when ex- 
posed to the sand-blast, that the threads of the network will, after a few 
seconds’ exposure, be imitated on the glass by bright interlacing lines, while 
the rest of the glass surface will be reduced to a ground or frosted state. 
The efficacy of the blast depends upon its velocity. The sand may be pro- 
pelled either by steam, water, or air, but steam is in general preferred where 
high velocities are required. When a large quantity of material is to be 
removed, as in the ornamenting of stone, a steam-jet of from 60 to 80 lbs. 
pressure is used. In this case the stencil' is made of iron or rubber ; but 
when a small quantity of material is to be worn away, or the surface merely 
depolished, as in ornamenting glass, a jet of air of from —th to 1 lb. pressure 
is preferred. With a low pressure, soft and delicate substances, such as 
paper designs, lace, leaves, &c., cemented on glass, may be used. With a 
steam-jet using two horse-power of steam at 70 lbs. pressure, and one pint 
