716 GEOLOGY OF OHIO. 
with oil, and the sockets are beautifully true and correct. The drying, 
setting and burning need no special attention. The kilns used are just 
like the stone-ware kilns; they are oblong, end-fired down-drafts, about 
30 to 35 feet long, and 15 to 20 feet wide, with an average capacity of 
about 40 tons. The burning takes six days. 
The character of Akron ware has already been hinted at in the 
description of the river pipe. It is a smooth, handsome ware, well- 
shaped, of a beautiful dark, red-brown color, and remarkably uniform. 
On its fracture it shows the red color of a brick or even a darker, which 
shows the presence of iron in that peculiar state so hard to define, which 
is necessary to the development of the high color; the per cent. of iron 
must be high, yet but little of that offensive blotching seen on the river 
ware can be noticed. The weakening of the whole ‘structure by the 
concentric cracks due to the pressing is the worst fault of the pipe. 
As to the inability of the Akron works to make the Cincinnati Stan- 
dard pipe, this is to be said. The increase of thickness of their pipe, 
with the same amount of drying which they now give it, is liable to cause 
large flakes to spall off from the sides of the pipe when heated in the kiln. 
With a longer and hotter drying they could make these thick pipe, but as 
their capacity is used to the fullest rate now, they are under no necessity 
to begin its manufacture. One point where they hold a decided advan- 
tage over the River district, is the use of the patent device for making 
curves, elbows, S’s and traps. They can control the position of the core 
inside the mud-drums by a lever, and by moving it so as to make one 
aperture smaller than the other, the clay issues the fastest on the 
thinnest side and the pipe takes a curve shape. Also by using a softer 
clay on one side than the other, the softest part issues faster and the 
pipe curves. The use of the movable core is so nicely manufactured 
that such curves as the letter S, and the stench traps, can be made with- 
out help from the hands. This is a patented principle, and the Akron 
works have a monopoly on it, and refuse to share with other parties. 
The catalogues and circulars of the Akron manufacturers claim 
that they sell a vitrified pipe. But the word vitrified has a definite 
signification. It would require, if properly applied, that the clay should 
have been fused to a glass, or that it should have undergone incipient 
fusion, or that its free silica and fluxing impurities should have been 
made to combine. But none of these conditions are met. The fracture 
of the Akron pipe is not in the least vitreous. On the contrary, parti- 
