MOll 



reason that, if to common mortar one j 

 fourth part of lime, reduced to pow- i 

 der without being slacked, be added, j 

 the mortar, when dry. acquires much 

 greater solidity than it otherwise 

 would do. This was first proposed i 

 by Loriot ; and afterward Morveau 

 found the following proportions to an- 

 swer best : 



Parts. 



Fine sand 3 



Cement of well-baked bricks .... 3 



Slacked lime 2 



Unslacked lime _2 



10 



The same advantages may be ob- 

 tained by using as little water as pos- 

 sible in slacking the lime. Higgins 

 found that the addition of burned 

 bones, in the proportion of not more 

 than one fifth of the lime employed, 

 improved mortar by giving it tenaci- 

 tv, and rendered it less apt to crack." 



'mortar, hydraulic. 



" When a little clay is added to mor- 

 tar, it acquires the important property 

 of hardening under water, so that it 

 may be employed by the farmer in 

 places which are constantly exposed 

 to the action of water. Limestone is 

 found not unfrequently mixed with 

 clay ; and in that case it becomes 

 brown by calcination, instead of white. 

 These native limestones are employ- 

 ed for making icater mortar ; but 

 good water mortar may be made by 

 the followin<r process : Mix together 

 four parts of bine clay, six parts of 

 black oxide of manganese, and 90 

 parts of limestone, all in powder ; 

 calcme this mixture to expel the car- 

 bonic acid ; mix it with 60 parts of 

 sand, and form it into a mortar with 

 a sufficient quantity of water. The 

 best mortar for resisting water is 

 made by mixing lime with puzzolano, 

 a volcanic sand brought from Italy. 

 Morveau informs us that basalt, which 

 is very common, may be substituted 

 for puzzolano. It must be heated in 

 a furnace, thrown while red-hot into 

 water, and then passed through a 

 sicvG.'' 



MORTIFICATION. Gangrene ; 



the death of a part of the body. When 



it occurs in the limbs, a distinct line 



of separation of a red colour may be 



U u 



MOS 



seen between the mortified and living 

 parts ; the limb should be removed 

 as soon as possible above the healthy 

 part. Mortification of internal or- 

 gans, when extensive, is necessarily 

 fatal ; when it comes on, there is 

 great loss of strength, freedom from 

 pain, usually a disagreeable or gan- 

 grenous odour, delirium, cold sweats, 

 and death. The lungs are most sub- 

 ject to gangrene, as a consequence 

 of infiammation. Sloughs and spha- 

 celus are small portions of gangrenous 

 fiesh removed from wounds. 



MORTISE. The union of two pie- 

 ces of wood or other substance, by 

 introducing one into a hole made ia 

 the other : the former is called the 

 tenon. 



MORUS. The generic name of 

 the mulberry, now often applied to 

 the Chinese, or M. multicauUs. 



MOSAIC WORK. Inlaying pave- 

 ments, walls, &c., with' small dies of 

 different shapes, colours, and mate- 

 rials, more especially to represent 

 historical subjects. 



MOSSES. Musci. In common 

 language, any minute, small-leaved, 

 cryptogamic plants. Thus, club-moss 

 is a lycopodium ; Iceland and rein- 

 deer mosses are lichens, and the nu- 

 merous species of Jungermannia are 

 all comprehended under the same 

 term ; but in systematical botany, 

 no plants are considered mosses ex- 

 cept such as belong to the natural or- 

 der Brijacea or Musci. Such plants 

 are simple-leaved, without spiral ves- 

 sels or stomata ; with a distinct ax- 

 is of growth, and with the sporules, 

 or reproductive matter, enclosed in 

 cases, called sporangia or thecse, cov- 

 ered by a cap or calyptra ; they have 

 cases, called staminidia, containing 

 powdery matter. None of the moss- 

 es are of any known use, except for 

 the purpose of packing plants, and 

 surrounding their roots when they 

 are sent to a distance. 



MOSS LANDS, or MOSSES. See 

 Moor. 



MOSS IN PASTURES. See Mead- 

 ows. Scarifying and manuring with 

 ashes form the most ready method of 

 treatiaff l1"-r defect 



505 



