CEM 



CEN 



iiite in some hours dries to a hard mass. 

 Almond paste will answer the same pur- 

 pose. The use of the above lute is so ex- 

 tensive, that no other is required in clos- 

 ing glass vessels in preparing all com- 

 mon distilled liquors ; and it will even 

 keep in ammonia, and acid gases, for a 

 longer time than is required for most ex- 

 perimental purposes. It begins to scorch 

 and spoil at a heat much above boiling, 

 and therefore will not do as a fire-lute. 

 It is still firmer, and dries sooner, when 

 made up with milk, or lime-water, or 

 weak glae. A number of very cohesive 

 cements, impervious to water and most 

 liquids and vapours, and extremely hard 

 when once solidified, are made by the 

 union of quick-lime with many of the ve- 

 getable or animal mucilaginous liquors. 

 The variety of these is endless. We may 

 first mention the following, as it has been 

 extensively employed by chemists for 

 centuries. Take some whites of eggs 

 with as much water, beat them well to- 

 gether, and sprinkle in sufficient slaked 

 lime to make up the whole to the con- 

 sistence of thin paste. The lime should 

 be slaked by being once dipped in water, 

 and then suffered to fall into powder, 

 which it will do speedily, with great emis- 

 sion of heat, if well burnt. This cement 

 should be spread on slips of cloth, and 

 applied immediately, as it hardens or sets 

 very speedily. While hardening it may 

 be of use to sprinkle over it some of the 

 lime in fine powder. This cement is of- 

 ten more simply and as conveniently ma- 

 naged, by smearing slips of linen on both 

 sides with white of egg, and when appli- 

 ed to the joining of the vessels, shak- 

 ing some powdered lime over it ; it then 

 dries very speedily. Another lute of the 

 same kind, and equally good, is made by 

 using a strong solution of glue to the lime, 

 instead of the white of egg : it sets equal- 

 ly soon, and becomes very hard. A mix- 

 ture of liquid glue, white of egg, and 

 lime, makes the lutcT one, which is so firm, 

 that broken vessels united with it are al- 

 most as strong as when sound. None of 

 these lutes, however, will enable these 

 vessels to hold liquids for any great 

 length of time. Milk or starch, with 

 lime, make a good but less firm lute. A 

 very firm and singular lute of this kind is 

 made by rubbing down some of the poor- 

 est skimmed-milk cheese with water, to 

 the consistence of thick soup, and then 

 adding lime, and applying as above : it 

 answers extremely well. Lime and blood, 

 with a small quantity of brick-dust, or 

 broken pottery, stirred in, is used in 

 some places as a very good water-ce- 



ment for cellars and places liable to 

 damp. 



All the above-mentioned cements, with 

 lime, become very hard by drying, inso- 

 much that they cannot be separated from 

 glass vessels without the help of a sharp 

 knife and some violence ; and hence deli- 

 cate vessels and long thin tubes, cement- 

 ed with it, are apt to break when the ap- 

 paratus is taken down, and sometimes 

 even by the mere force of contraction in 

 setting. It is a great advantage, how- 

 ever, that they may be applied imme- 

 diately to any accidental crack or failure 

 of the lute already on, notwithstanding a 

 stream of vapour is bursting through ; 

 and in large distillations it is of advantage 

 always to have some of the materials at 

 hand. 



CENCHRUS, in botany, a genus of the 

 Polygamia Monoecia class and order. 

 Natural order of Grasses. Essential cha- 

 racter: invol. laciniate, echinate, two 

 flowered ; calyx glume two flowered, one 

 male, the other hermaphrodite; Herm, 

 corolla glume awnless ; stamina three ; 

 seed one : male, corolla glume awnless ; 

 stamina three. There are eleven species, 

 all natives of both Indies. 



CENSOR of books, is a body of doc- 

 tors or others established in divers coun- 

 tries to examine all books before they 

 go to the press, and to see they contain 

 nothing contrary to faith and good man- 

 ners. 



In England, we had formerly an officer 

 of this kind, under the title of licenser of 

 the press ; but since the revolution our 

 press has been laid under no such re- 

 straint. 



CENT, in commerce, an abridgement 

 of centum, is used to express the profit 

 or loss arising from the sale of any com- 

 modity. Thus we say, there is 10 per 

 cent, profit, or 10 per cent, loss which is 

 one-tenth profit, or one-tenth loss, upon 

 the sale of the whole. 



CENTAUREA, in botany, a genus of 

 the Syngenesia Polygamia Frustranea 

 class and order. Natural order of com- 

 pound flowers. Cinarocephabe, Jussieu. 

 There are seventy-seven species, of which 

 we shall only mention C. moschata, pur- 

 ple sweet centaury, which is an annual, 

 and has been many years propagated in 

 the English gardens, under the title of 

 Sultan flower, or sweet Sultan. It was 

 brought from the Levant, where it grows 

 naturally in arable land among the corn ; 

 it sends up a round, channelled stalk, 

 nearly three feet high, which divides in- 

 to many branches, from the sides of which 

 come out long naked peduncles, each 



