C U L 



relates to the ftruaure of cryftals, and the fymboUc 

 of delcribing the decrements by which the fecondary cr 



are formed. The 



CRY 



I'Lt prtceding illuftrations of M. Haiiy's mode of de- 

 J.oting the ftrudture of cryftals by fymbols, are given in 

 detail to enable the ftudent to make a figure of a cryftal 

 from the f)-mbol reprefenting the laws of its formation. 

 Shorter rules for enabling the ftudent merely to read and 

 underftand this mode of notation will fuffice. 



1. The letters P, M, T, denote the facesof the nucleus or 

 primitive cryftal, or indicate that the faces are paraDel to 

 the faces of the primitive cr)ftal marked with the fame letters. 



2. Every vowel in the fymbol indicates a folid angle, 

 marked with the fame letter as in the nucleus. Every confo- 

 nant indicates the edge which has the fame letter in the figure. 



3. Each letter contained in the fymbol is underftood with 

 the figure belonging to it to reprefent all the fame letters, 

 and the angles or edges which have the fame funftion. 



4. Every number joined to a letter indicates a decrement reprefents the fecondary rhomb, fg. 24. with "the'^three 

 fetting out from the angle or the edge denoted by that fuperior edges, and the three inferior ones cut off or trun- 



mode 



a . - „, ,^ lary cryftals 



figures m Plates II. III. IV. V. VI 

 Cryjlallography, which we have defcribed, are copied from' 

 Hauy'sTraite de Mineralogie, tom. i., and containwhat he has 

 giveii m lUuftration of the ' theory of cryftalhzation.' The 

 apphcation of geometry and analyfis, to determine the^laws 

 of decrement from the meafurement of the angles, which has 

 been fo ably made in the above-named work by this illuf- 

 tnous cn,-ftallographer, would require for its explanation a 

 more ample fpace than would be confiftent with the prefent 

 article, which is intended to fupply what was defeftive in the 

 explanation of the plates under the article Crystal, and 

 to correft the references that were there erroneoufly given. 

 (See Crystal.) We omitted to ftate, that P/a/? II. if?-. 2c.' 



»-*^r>for.snf f- ♦!.« r J _1 L r - ■ 1 ^ *^ ° , ^ 



letter. If the number be a whole one, it indicates the 

 ranges in breadth, fuppofing each plate to have only the 

 thicknefs of one molecule. If the number be a fraftion, the 

 numerator indicates the number of ranges fubtrafted in 

 breadth, and the denominator the number of ranges fub- 

 trafted in height. 



5. The number is placed above the letter to (hew that 

 the decrement afcends, or below it to (hew that it defcends, 

 fetting out from the angle or edge marked by the letter. 

 If it be placed either on the right or left hand of the letter, 

 it indicates a decrement to the right or left of the edge or 

 angle marked by the letter, 



cated r, r, r, r', r', r' ; by cutting other laminx parallel to 

 each of the faces r, r, r, &c. we (hall at length extrad the 

 primitive nucleus A E, O I, Jig. 24. 



CSHATRIYA, or Chatterie, denotes in India a 

 man of the fecond or mihtary caft. See Cast. 



CUCKFIELD. In 181 1, the parifti of CuckfieJd 

 contained 300 houfes, and 208S perfons ; -viz. 1063 males, 

 and 1025 females : 251 families being employed in agricul- 

 ture, and 123 in trade, &c. 



CUCKOW-Spit. Add— This cuckow-fpittle encom- 

 palfes the larva of a fpecics of cicada, which is denominated 

 C. fpumaria, or cuckow-fpit cicada, from the circumftance 



6. When a letter is twice repeated with the fame number of its larva being conftantly found enveloped in a mafs of 

 placed on different fides, as * G G " or G ^ ' G, ^ A A " or white froth adhering to the leaves and ftems of vegetables 



A' ''A, the two edges or two angles which it marks fhould 

 be confidered in the figure in the fame relative pofitions. 

 Thus, ^ G G ^ indicates the effeft of decrement by two 

 ranges on the edge G fituated at the left, and of a fimilar 

 decrement on the edge G fituated at the right. 



7. When a letter has the fame number both on the right 

 and left fide, as ' G S it applies equally to all the edges G. 

 The fame applies to the letters which denote the angles. 



8. The parenthefis, as, for example, (OD', F%) indi. 



cates an intermediate decrement. The letter O indicates, 

 that an afcending decrement of three ranges takes place on 

 the angle O ; D ', that one molecule is fubtrafled along the 

 edge D ; and F", that two molecules are fubtrafted on the 

 edge F. 



9. Every fmall letter in the fymbol indicates the angle or 

 the edge diametrically oppofite to that which has the fame 

 capital letter in the figure, where the fmall letter is omitted 

 as fuperfluous. The letter e is, however, never omitted in 

 the rhomboid ; it indicates, according to the principle, the 

 letter oppofite to E. 



10. When the lai-ge and fmall letters of the fame name 

 are introduced into the fymbol with diffei-ent numbers 

 attached to them, the two oppofite edges or angles denoted 

 by thefe letters are conceived to undergo exclufively the 

 law of decrement, indicated by the number attached to the 



*^"7.' Every letter, whether large or fmall, marked by a ,, •^"- ^"- ^veceptacieceuu.,^. ue.u.,„.uuu.^u.,.,...., 



11. A^.uijf , b ^^ ' 1 Common calyx of one leaf, covered with imbneated Icales. 



number having a zero attached to it, as E, indicates that the 

 decrement denoted by that number does not take place on 

 the angle or edge which the letter reprefents. 



The above account of the theory of cryftallization, and 

 the notation of cryftals, may fuffice with what has been 

 before given under the article Crystal, to convey ample 

 info»maiion of the abbe Haiiy's ingenious fyftem, fo far as 



This froth, called cuckow-fpittle, is found during the ad- 

 vanced ftate of fummer, and is the produftion of the in- 

 cluded larva, which, from the time of its hatching from the 

 egg depofited by the parent infeft, continues occafionally to 

 fuck the juices of the item on which it refides, and to dif- 

 charge them from its vent in the form of very minute 

 bubbles, till it covers itfelf with a large mafs of froth, and 

 it is fometimes fo overcharged with moifture that a drop 

 may be feen lianging from its under furface. Shaw's Zoo- 

 logy, vol. vi. 



CUCULUS, 1. 4, add — Dr. Leach, however, obferves, 

 that this property does not belong to this kind of feet, 

 which can be coniidered merely as fimple feet, having two 

 toes before and two behind. Col. 2, 1. 21, after infefts, 

 add — and ou larvje or caterpillars ; I. 35, add — For the 

 natural hiftory of this bird, fee Dr. Jenner's curious paper 

 in the Phil. Tranf. for 1788, pt. ii. 



CUD-BEAR. See Lichen Tartmus. 



CULLUMIA, in Botany, dedicated by Mr. Brown, to 

 the honour of the late fir John Culhim, bart., an elegant 

 and accomplilhed fcliolai- and botanift ; as well as of his 

 brother the prefent fir Thomas Gcry CuUum, bart. F.L. S. 

 an excellent Britifli botanift, one of the moll ardent culti- 

 vators of this lovely fcience, whole friend(hip alone can be 

 more valued than his various and extenfive information. — Br. 

 in Ait. Hort. Kew. v. 5. 137. — Clafs .ind order, Po/ygamia- 

 frujlranea. Nat. Ord. Compofitx, Linn. Corymbifen, JulT. 



ElT. Ch. Receptacle cellular. Seeds fmooth. Dovmnone. 



dfiaris. Fringed CuUumia. Ait. n. I. (Berkheya 



Willd. Sp. PI. v. 3. 2273. Gorteria ciharis ; Linn. 



1284. Carhna foliis imbricalis, &c. ; 151. 1.54. 



Leaves ovate, fmooth, imbricated, fringed with a 



double row of briftles, and tipped with a reflexed fpine. 



2. C./eto/a. Recurved fmooth-leaved CuUumia. Ait. 

 n. 2. (Berkheya fetofa; Willd. ibid, excluding Comme- 



lin'* 



I. c 



ciharis 

 Sp. PI. 



f. 1.- 



