EM 13 



EMU 



conveniently used for this purpose, 

 and they may be carried out so far 

 as to empty themselves below low- 

 water mark. But when the embank- 

 ment is very extensive, and there are 

 streams flowing through the part 

 which is embanked, larger flood-gates 

 and more extensive works are neces- 

 sary. These being opened and shut 

 as occasion may require, serve to 

 keep the channel clear, by producing 

 occasionally a considerable rush of 

 water to carry away mud and sand, 

 which would otherwise have accu- 

 mulated at the mouth of it. When 

 the level of the land which is embank- 

 ed is below the usual level of the wa- 

 ters which are without, the water is 

 raised by means of engines over the 

 banks, as is the case in the fens. 



" In the forming of the banks, where 

 the soil may not be quite impervious 

 to water, it is useful to begin by dig- 

 ging a ditch in the line of the intend- 

 ed bank, of such a depth as to reach 

 an impervious subsoil. This ditch is 

 to be hlled up with clay or tempered 

 earth, and as the bank is raised, the 

 middle of the bank should be com- 

 posed of the same materials, which 

 will thus form a vertical wall, A B, up 

 to the top ; and the more porous earth 

 being heaped up against the sides of 

 this wall will form the slopes of the 

 bank ; thus the whole will be perfect- 

 ly impenetrable to the water. The 

 clay should be well trod in with the 



A 



feet in a moist state, and no pieces 

 of wood, or even straw, should be in 

 it, for a straw may be the cause of 

 the water finding a passage through 

 a bank, and this passage gradually 

 widening will soon produce a hole, 

 which may in the end cause the de- 

 struction of the bank. Moles and 

 worms are great enemies to dikes. 

 260 



In Holland the storks are held in 

 great veneration, and are never mo- 

 lested, because they are supposed to 

 destroy a species of worm which oft- 

 en does great mischief to the dikes by 

 perforating them." — {W. L. Rham.) 



EMBROCATION (from sfiCpExa, 1 

 vioistc7i). A spirituous, saponaceous, 

 or oily application rubbed on the skin 

 to relieve pain or numbness. 



EMBRYO (from e/xSpvov, I bud 

 forlh). The growing point, eye, or 

 chit of a seed. The young of ani- 

 mals in the act of development, or 

 foetus. 



EMBRYOTOMY (from sfifipvov, 

 and Tefivu, I cut). The cutting of 

 the embryo or foetus out of the womb 

 in such cases as endanger the life of 

 the parent. 



EMERY. A sand of corundum ol 

 extreme hardness, capable of wear- 

 ing down all minerals and metals ex- 

 cept the diamond. 



EMESIS (from f/^ew, I vomit). The 

 act of vomiting. 



EMETIC. A drug producing vom- 

 iting. Ipecacuanha, tartar emetic, 

 salt, and green vitriol are the com- 

 monest emetics. 



EMETIC, TARTAR. Tartrate of 

 potash and antimony, a white, solu- 

 ble salt, emetic in doses of one to 

 two grains, and purgative and sudo- 

 rific in doses of half a grain. It re- 

 duces the activity of the circulation, 

 and is therefore an admirable febri- 

 fuge. 



EMETINE. The active principle 

 of ipecacuanha. 



EMOLLIENTS. Medicines which 

 soothe and soften any part of the 

 body, as warm water, &c. 



EMPHYEMA (from tv, and nvov, 

 pus). A collection of purulent mat- 

 ter in the chest, produced chiefly by 

 inflammation. 



EMPHYSEMA (from e/iibvaau, 1 

 inflate). A collection of air in the cel- 

 lular tissue ; hence emphysematous. 



EMPYREUMA (from tfinvpevu, 1 

 kindle). An odour of burned matter ; 

 hence empyreumatic. 



EMULSIN. A modification of al- 

 bumen found in almonds and other 

 seeds, and capable of acting in a pe- 



