vessel into which the porter is run before being pumped into the vats) with the mild beer. This mode of Working may also be unsafe; for unless the fermentation has been vigorous and healthy, and the old beer brought into a fit state for mixing, no combination will take place; the beer will retain a double flavour, and be occasionally unfit to be sent out, unless by being brought into proper condition, and again mixed off with mild beer. From the above remarks, it will be seen that marrying or mixing beers is a very dangerous process, unless when thoroughly understood by the operator.
Old beer can never be in a proper state for mixing off, unless when brought round (as it is called) for that purpose. This can only be done by again bringing it into a state of fermentation in the vat: after which, if properly treated, it will generally become bright and sparkling; that is to say, if it has not got so bad as to be totally irrecoverable, or unfit for use in any way excepting in making blacking. It will then at once combine with any sound mild beer, and, instead of injuring, will improve the flavour. Judiciously to bring on the above-mentioned fermentation in the vat, and at the same time so as not to carry it too far, requires a good deal of skill, and can only be accomplished by those who have been accustomed to such management. Where the process of fermentation is properly and scientifically conducted, these artifices, rendered neces-
