EMERSON EMIGRATION. 



851 



fine emeralds are stated to have formerly been be- 

 queathed to different monasteries on the continent ; 

 but the greatest part of them are said to have been 

 sold by the monks, and to have had their place sup- 

 plied with coloured glass imitations. These stones 

 are seldom seen of large size, and at the same time 

 entirely free from flaws. The emerald, if heated to 

 a certain degree, assumes a blue colour, but it 

 recovers its own proper tint when cold. When the 

 heat is carried much beyond this, it melts into an 

 opaque, coloured mass. The Oriental emerald is a 

 variety of the ruby, of a green colour, and is an 

 extremely rare gem. See Beryl. 



EMERSON, WILLIAM, an eminent English mathe- 

 matician, was born at Hurworth, near Darlington, 

 in the year 1701. Having derived from his parents 

 a moderate competence, he devoted himself to a life 

 of studious retirement. From the strength of his 

 mind and the closeness of his application, he acquired 

 a deep knowledge of mathematics and physics, upon 

 all parts of which he wrote sound treatises, although 

 with few pretensions to originality of invention, and 

 in a rough and unpolished style. He died in 1782, 

 in his eighty-first year. 



EMERY, JOHN, an actor of eminence, was born at 

 Sunderland, in the palatinate of Durham, December 

 22, 1777, and educated at Ecclesfield in Yorkshire, 

 where he acquired that knowledge of the provincial 

 dialect which afterwards contributed so much to his 

 celebrity. In the unsophisticated rustic or the stupid 

 dolt, lie was excellent ; while in some parts, written 

 purposely for him, such as Tyke in the School of 

 Reform, and Giles in the Miller's Maid, his acting 

 was truly terrific and appalling. The portraying of 

 rough nature, fine simplicity, and strong passion, was 

 his forte ; and in the latter, especially, he ever 

 excited -the approbation of the best critics. In private 

 life, he was much esteemed. He died in January,1822. 



EMERY, a very hard mineral, of blackish or blu- 

 ish-grey colour, is chiefly found in shapeless masses, 

 and mixed with other minerals. It contains about 

 80 parts in 100 of alumina, and a small portion of 

 iron, is usually opaque, and about four times as heavy 

 as water. The best emery is brought from the Le- 

 vant, and chiefly from Naxos, and other islands of the 

 Grecian archipelago. It is also found in some parts 

 of Spain, and is obtained from a few of the iron 

 mines in Great Britain. In hardness, it is nearly 

 equal to adamantine spar, and this property has ren- 

 dered it an object of great request in various arts. It 

 is employed by lapidaries in the cutting and polishing 

 of precious stones ; by opticians, in smoothing the 

 surface of the finer kinds, preparatory to their being 

 polished ; by cutlers and other manufacturers of iron 

 and steel instruments ; by masons in the polishing of 

 marble ; and, in their respective businesses, by lock- 

 smiths, glaziers, and numerous other artisans. For 

 all these purposes, it is pulverized in large iron mor- 

 tars, or in steel mills , and the powder, wlu'ch is rough 

 and sharp, is carefully washed, and sorted into five or 

 six different degrees of fineness, according to the de- 

 scription of work in which it is* to be employed. See 

 Corundum. 



EMETIC (emeticus ; from tp'uu, to vomit); that 

 which is capable of exciting vomiting, independently 

 of any effect arising from the mere quantity of matter 

 introduced into the stomach, or of any nauseous taste 

 or flavour. The susceptibility of vomiting is very 

 different in different individuals, and is often consi- 

 derably varied by disease. Emetics are employed in 

 many diseases. When any morbid affection depends 

 upon, or is connected with over-distension of the sto- 

 mach, or the presence of acrid, indigestible matters, 

 vomiting gives speedy relief. Hence its utility in 

 impaired appetite, acidity in the stomach, in intoxi- 



cation, and where poisons have been swallowed. In 

 the different varieties of febrile affections, much ad- 

 vantage is derived from exciting vomiting, especially 

 in the very commencement of the disease. In high 

 inflammatory fever, it is considered as dangerous, and 

 in the advanced stage of typhus, it is prejudicial. 

 Emetics, given in such doses as only to excite nausea, 

 have been found useful in restraining hemorrhage 

 Different species of dropsy have been cured by vo- 

 miting, from its having excited absorption. To the 

 same effect, perhaps, is owing the dispersion of va- 

 rious swellings, which has occasionally resulted from 

 this operation. The operation of vomiting is danger- 

 ous or hurtful in the following cases : where there is 

 determination of the blood to the head, especially in 

 plethoric habits ; in visceral inflammation ; in the 

 advanced stage of pregnancy ; in hernia and prolap- 

 sus uteri ; and wherever there exists extreme general 

 debility. The frequent use of emetics weakens the 

 tone of the stomach, and should never be resorted to 

 but hi cases of extreme urgency. An emetic should 

 always be administered in the fluid form. Its opera 

 tion may be promoted by drinking any tepid diluent 

 or bitter infusion. 



EMETINE is a peculiar vegetable principle, ob- 

 tained from the ipecacuan root, of whose emetic pro- 

 perties it is conceived to be the sole cause. It is 

 obtained by digesting the root first in ether and then 

 in alcohol. The alcoholic infusion is evaporated to 

 dryness ; and to the residuum, re-dissolved in water, 

 acetate of lead is added, which produces a precipi- 

 tate.' The precipitate is washed, diffused in water, 

 and decomposed by a current of sulphureted hydro- 

 gen gas. Sulphuret of lead falls to the bottom, and 

 the emetine remains in solution. By evaporating the 

 supernatant fluid, this substance is obtained pure. It 

 forms transparent, brownish-red scales : it is desti- 

 tute of smell, but has a bitter, acrid taste. At 'a 

 heat somewliat above that of boiling water, it is 

 resolved into carbonic acid, oil, and vinegar. In 

 a dose of half a grain, it acts as a powerful emetic, 

 followed by sleep : six grains produce violent vo- 

 miting, stupor, and death. 



EMEU, or NEW HOLLAND CASSOWARY. 

 See Cassowary. 



EMIGRATION ; removal from one country to 

 another, for the purpose of permanent residence. 

 Every man born free, or who had obtained his free- 

 dom, formerly had the right of emigrating. But as 

 capital and power were lost to a state by the removal 

 of its inhabitants, it was considered, that emigration 

 ought to be forbidden, and the people only allowed to 

 remove from one place to another within the limits of 

 state. Experience, however, proved that such 

 prohibitions were fruitless, and the only way to guard 

 igainst emigrations was by the fullest protection of 

 property ; by granting freedom of conscience, and 

 ;he undisturbed exercise of religion ; and by not 

 aanishing subjects from their country on account of 

 Jieir religious opinions, as was once done (e. g., in 

 France and Saltzburg) ; by allowing them, under the 

 Drotection of judicious laws, with the assurance of 

 reedom in trade and commerce, the undisturbed en- 

 oyment of the fruits of their industry ; by not ex- 

 josing them to the oppression of magistrates ; and 

 >y delivering them from the fear of unreasonable or 

 arbitrary taxes. 



When we consider how much resolution is required 

 ;o abandon for ever the home to which man is bound 

 :>y the strongest ties of recollection, language, and 

 labit, to seek an uncertain fortune in a land of stran- 

 ers, there is no reason to believe, tliat large masses 

 will ever emigrate without the most urgent motives. 

 Wherever emigration is common, it is not an evil it- 

 self, but only the consequence and symptom of an 

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