Rensselaer Union, Volume 7, Number 1, Rensselaer, Jasper County, 24 September 1874 — Strong Mortar. [ARTICLE]

Strong Mortar.

So very marked is the mortarused in modern buildings as poor, compared with that long ago used* that various attempts hqve been made to ascertain the “ secret,” if secret it was, of the composition of the Old builders in mortar-making. One “secret” which the old builders possessed tyg may quietly here impart to those of the present day; that is, that to make good mortar, good lime and plenty of it must be used; the old builders did not use a composition nearly all sand, and that sand not fit often to be used, and then call it mortar, as do the builders of the day oftentimes. When

we examine almost any piece of modern work, we find that the mortar hardons very slowly, and even when hardened as much as it will harden, it crumbles away, loses cohesiveness, so much so that in many cases it is quite an easy matter to detach the stones or bricks trom one another and from the mortar. The very opposite characteristics are found in ancient work, and on examination it has been seen that the mortar has in great part been converted into silicates, entering into close union with the particles of quartz. It is to these silicates "that mortar, owes its firmness, antTff is~ to the slowness with which silicates form in modern mortar, and small proportion of these present in it, that this owes its poverty. A method of setting free the silicious earth, and promoting the rapid formation of silicates, has been discovered by a Prof. Artus, and which yields a mortar resembling in its characteristics those of the ancient kinds. The great recommendation the process possesses is its simplicity. Lime is in the first instance well slacked, and mixed carefully with finely-sifted sand; to the mass is added a quantity of unslacked lime to the extent of one-fourth of the sand in the first instance mixed with the slacked lime; mix the whole thoroughly, the mass heats and the mortar may be at once used. When the mortar is not wanted for immediate use, the first process only is carried out, namely, mixing the sand with the fine-slacked lime; when wanted for use the unslacked lime has to be added. A very strong mortar is said to be the result.— Builder.