incurred, as the gas does not require purification.

At Colinsburgh (the village alluded to), I was informed that the man
sent by the patentees could produce 100 cubic feet of gas per gallon of
oil; but they had no means of testing the illuminating power. The gas
company's own servant, however, only produced 80 cubic feet per gallon,
which they attributed to his want of experience in knowing the proper
heat at which to work the retorts. Whether or not this was so I cannot
tell; but of this I am certain, that the statement made that the gas
does not require purification will not bear investigation. When I tested
it for sulphureted hydrogen and for ammonia, both were indicated in such
an unmistakable manner as none of us would care to see in our coal gas
as sent out to the consumer.


PRICES OF RESIDUAL PRODUCTS.

What is of far more real consequence to us than the possible change from
coal gas to oil gas, however, as long as we remain manufacturers of the
former, is the value of our residual products, which has suffered so
great and sudden a decline in value, for which various remedies have
been proposed, though none of them, I regret to say, have as yet
restored anything like the former value. A statement of the highest
prices realized for coal tar products, and a comparison with those
obtained on the 30th of March last year and at the same time this year,
may not be uninteresting:

+--------------------------------------------------------------------+
| | Highest | Price on | Price on |
| | Price | March 30, | March 30, |