Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 3, 1802).djvu/251

229&#93; MOR ereding walls, houses, &:c. Mortar being an article of ex- tensive utility, it becomes an ob- jeft of considerable importance to discover such a method of prepar- ing it, together A^ith such materials, as will perfectly cohere, and at the same time resist the attion of the M-eather, Having already treated, at sotnt length, on this subjed, under the head of Cement, we shall at pre- sent state two of the most simple m.ethods of preparing strong and dlirable mortar. The proportions of lime and sand usually employed in making the common mortar, are two parts of the former to th-ee of the latter, which are mixi'd up with soft wa- ter ; but its quality and durability will, according to Dr. Axdersox, be considerably improved, if the lime be slaked, and the sand mix- ed up with lime-water, instead of the common. The reasori assign- ed for this opinion is, that the fluid drawn from wells contains a large portion of fixed air ; which, by mingling with the mortar before it is used, reduces the quick-lime in- to a kind of inert calcareous earih, similar to chalk, and thus spoils the cement. But, if the mortar be ^'orked up in a perfectly caustic state, it attracts the air so slowly, that it concretes into a kind of stony matter, which, in the course of time, becomes a<> hard as the rock from which the lime-stone was taken. In the year J '/'/J was published (in French), an ingenious "/w^tm//;/ canrernivg the Manner in rvhich the Romans prepared ike Lime they used ill Building ; as also on their met hod of mixing and using their Mortar)' by M, De Lafaye. — The principal circiunstauce appears ?^r o R [229 to be the mode of slaking the lime without liquefying it, so as to reduce it to powder j and at the same time to leave it sufficiently caustic to yield a strong mortar j which, in proportion to its age, v.-ill acquire additional strength. — To elteft ';uch objett, it is requi- site to select good fresh iime, made of hard lime-stone, which is to be broken into pieces of the size of an egg. These should be pb.ced in a shallow open basket, which ought to be plunged into water, till the surface of die fluid begin to boil. The basket is then drawn out, and suffered to drain for a short time ; after which tiie lime is put into casks, where it speedily grows hot, and crumbles into powder. The lime thus prepared, is to be mixed with various compositions of mortar, according to the pur- poses for which they are designed. It maybe preserved for a consider- able time, and will retain its use- ful properties, by simply coverino- the casks with straw. — M. Guy- Tox states, in a late volume of tli« Annales de Chimie, that he em- ployed this lime, 18 years since, in the construction of a small aque- du6t, which was intended to con- vey water to an artificial nitre-bed. The mortar consisted of equal parts of the following three ingredients, namely, sand, fragments of cal- careous stone, and iime .slaked according to the directions above given : in a short time, it acquired an uncommon degree of firmness, yhich has remained unimpaired sincethat period. — SeealsoBuiLD- IXG, vol. i. p. 382. MORTIFICATION, or Spha- celus, in the animal economy, is generally defined to be a total ex- tih6tion of the natural beat of the Q 3 body,
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