London Labour and the London Poor, Vol. 2

by Henry Mayhew

Notwithstanding the reluctance of some of the contractors to give information on this, or indeed any subject connected with their trade, I have ascertained from indubitable authority, that “mac” is disposed of in the following manner. Some, but this is mostly the mixed kind, is got rid of in any manner; it has even been diluted with water so as to be driven down the drains. Some is mixed with the general street ordure—about a quarter of “mac,” I was told, to three-quarters of dung and street mud—and shipped off in barges as manure. Some is given to builders, when they require it for the foundations of any edifices that are “handy,” or rather it is carted thither for a nominal price, such as a trifle as beer-money for the men. Some, however, is sold for the same purpose, the contractors alleging that the charge is merely for cartage. Some, again, is given away or sold (with the like allegation) for purposes of levelling, of filling up cavities, or repairing unevennesses in any ground where improvements are being carried on; and, finally, some is sold to masons, plasterers, and brickmakers, for the purposes of their trade.

Even for such purposes as “filling up,” there must be in the “mixed mac” supplied, at least a considerable preponderance of the pure material, or there would not be, as I heard it expressed, a sufficient “setting” for what was required.

As a set-off to what is sold, however, I may here state that 30s. has been paid for the privilege of depositing a barge-load of mixed street dirt in Battersea-fields, merely to get rid of it.

The principal use of the unmixed “mac” is as a component part of the mortar, or lime, of the mason in the exterior, and of the plasterer in the interior, construction of buildings, and as an ingredient of the mill in brick-grounds.

The accounts I received of the properties of “mac” from the vendors of it, were very contradictory. One man, until lately connected with its sale, informed me that as far as his own experience extended, “mac” was most in demand among scamping builders, and slop brickmakers, who looked only to what was cheap. To a notorious “scamper,” he one morning sent three cart-loads of “mac” at 1s. a load, all to be used in the erection of the skeleton of one not very large house; and he believed that when it was used instead of sand with lime, it was for inferior work only, and was mixed, either for masons’ or plasterers’ work, with bad, low-priced mortar. Another man, with equal knowledge of the trade, however, represented “mac” as a most valuable article for the builder’s purposes, it was “so binding,” and this he repeated emphatically. A working builder told me that “mac” was as good as the best sand; it made the mortar “hang,” and without either that or sand, the lime would “brittle” away.

“Mac” may be said to be composed of pulverised granite and rain water. Granite is composed of quartz, felspar, and mica, each in granular crystals. Hence, alumina being clay, and silex a substance which has a strong tendency to enter into combination with the lime of the mortar, the pulverizing of granite tends to produce a substance which has necessarily great binding and indurating properties.

From this reduction of “mac” to its elements, it is manifest that it possesses qualities highly valuable in promoting the cohesive property of mortar, so that, were greater attention paid to its collection by the scavenger, there would, in all probability, be an improved demand for the article, for I find that it is already used in the prosecution of some of the best masons’ work. On this head I can cite the authority of a gentleman, at once a scientific and practical architect, who said to me,—

“‘Mac’ is used by many respectable builders for making mortar. The objection to it is, that it usually contains much extraneous decaying matter.”

Increased care in the collection of the material would, perhaps, remove this cause of complaint.

I heard of one West-end builder, employing many hands, however, who had totally or partially discontinued the use of “mac,” as he had met with some which he considered showed itself brittle in the plastering of walls.