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the minhtry till the year 1686, when he was eleded profeflbr 

 of divinity at the univerlity of Franeker. In 1704 he ac- 

 cepted an invitation to fill the divinity chair at the univerlity 

 of Utrecht, a pod which he retained with great reputation 

 till his death in 1718, when he was in the 66th year of his 

 age. He was author of many works chiefly on theological 

 topics, among which are " A Commentary upor the Epiille 

 to the Ephelians ;" " An Analyfis of the Epiille to the 

 Coloffians ;" " An Analyils and Abridgment of the Pro- 

 phetical Books of the Old Teltament ;" " Two philo- 

 sophical DiHertations on Natural Religion, and one on 

 Innate Ideas." 



ROELLA, in Botany, fo named by Linnasus, in Hort. 

 Cliff. 492, to commemorate William Roell, profeflbr of 

 anatomy at Amiterdam, who enriched Cliffbrt's garden with 

 many rare plants, the feeds of which he had procured from 

 Africa and Japan. Among thofe from the Cape of Good 

 Hope, was the firft fpecies of the prefent genus. — Linn. 

 Gen. 88. Schreb. 118. Willd. Sp. PI. v. 1. 918. Mart. 

 Mill. Did. v. 4. Ait. Hort. Kew. v. I. 353. JuiT. 165. 

 Lamarck Illultr. t. 123. Ga:rtn. t. 31. — Clafs and order, 

 Pentandria Monogynia. Nat. Ord. Campanacete, Linn. Juli. 



Gen. Ch. Cal. Perianth fuperior, of one leaf, turbinate, 

 permanent, in five large, deep, lanceolate, acute, toothed 

 fegments. Cor. of one petal, funnel-fhaped, deciduous ; 

 tube rather Ihorter than the calyx ; limb fomewhat fpread- 

 ing, longer than the calyx, deeply five-cleft. Nedary of 

 five converging fcales, in the bottom of the corolla, perma- 

 nent. Stam. Filaments five, awl-fhaped, (landing on the 

 nedary ; anthers awl-fhaped, converging, equal in length 

 to the filaments, and on a level with the calyx. Pijl. Ger- 

 men inferior, oblong ; ftyle thread-fhaped, the length of 

 the ftamens ; ftigmas two, oblong, deprefled, fpreading. 

 Perk. Capfule cylindrical, fhorter than the calyx, crowned 

 with its enlarged fpreading fegments, two-celled, burfting 

 at the fummit. Seeds numerous, angular. 



Efl. Ch. Corolla funuel-ftiaped, chafed at the bottom by 

 valves bearing the itamcus. Stigma in two fegments. Cap- 

 fule inferior, cylindrical, opening at the fummit. 



Obf. Linnxus attributes two cells to the capfule ; 

 Gaertner only one. Probably one may be occafionally 

 abortive. The eflcntial diflinction feems to confilt in the 

 capfule having a vertical opening, inflead of difcharging 

 the feeds by torn lateral orifices, as in Campanula, to which 

 genus this is certainly, in other refpeds, very nearly allied. 

 All the known fpecies are natives of the Cape of Good 

 Hope, being green-houfe plants in England, and having 

 blue flowers. 



1. R. ciliata. Ciliated Roella. Linn. Sp. PI. 241. Hort. 

 Cliff, t. 35. Willd. n. I. Ait. 11. 1. Curt. Mag. t. 378. 

 (Campanula africana frutefcens aculeofa, flore violaceo ; 

 Comm. Hort. v. 2. 77. t. 39.) — Leaves lanceolate, fringed, 

 with a prominent point. Flo'vers terminal, folitary. — Found 

 in various parts of fouthern Africa. The Dutch have long 

 cultivated it. Mr. Mallon fent feeds to Kew in 1774. The 

 plant is not very common, though much to be admired for 

 the beauty of its flowers, which are produced in fueceflion, 

 throughout molt part of the iummer ; but it is not eafily 

 increased, nor long preferved, being impatient of our damp 

 winters. TUcJlem is (hrubby, of humble growth, branch- 

 ing in a determinate manner ; the tranches (lender, round, 

 leafy. Leaves copious, alternate, finall, of a pale dull green, 

 linear-lanceolate, fringed, each ending in a prominent, awl- 

 lliaped, rigid point. Flowers folitary at the ends of the 

 branches, an inch and half, or more, in diameter, their co- 

 lours well defcribed by Curtis as follows. " The bottom 

 of xhejlo-wer is white, of a yellowifh calt ; next fucceeds a 



Vol. XXX. 



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circle of deep blue, inclining to black, with a furface 

 highly glazed ; the next circle is greyifli-blue, refembling 

 fatin ; the next nearly white, and the outcrmoft, (or limb,) 

 pale purple." Each leaf of the plant is accompanied by 

 an axillary tuft of fmaller, obtufe, entire, naked ones. 



2. R. fquarrofa. Trailing Roella. Linn, Suppl. 143. 

 Thunb. Prodr. 38. Willd. n. 2. Ait. n. 2. — Leave, 

 ovate, recurved, toothed, fringed. Flowers terminal, ag- 

 gregate. Stem herbaceous, difl'ufe.— Gathered by Thun- 

 berg at the Cape, and fent from thence to Kew garden, by 

 MafTon, in 1787. It bloflbms in June. The branches are 

 more fpreading and decumbent, as well as of a lefs fluubby 

 nature, than the former. The fquarrofa of Bergius, from 

 whom the younger Linnaeus adopted the name, is defcribed 

 as zjhrub, with folitary j?oit><v\r. Ours, befides the terminal 

 tuft, has generally feveral fcattered lateral j?o<aw.r, on fhort 

 leafy (talks, or branches, which may explain this apparent 

 difagreement. 



3. R. decurrens. Decurrent Roella. L'Hcrit. Sert. 4. 

 t. 6. Willd. n. 3. Ait. n. 3. — Leaves lanceolate, entire, 

 fringed, decurrent. Flowers folitary, terminal. — Sent from 

 the Cape, by Mr. MafTon, in 1787. This fpecies is annual, 

 flowering in September. The root is fmall and taperino-. 

 Stem much branched from the very bottom, fpreading and 

 partly decumbent, hairy. Leaves ovato-lanceolate, fringed, 

 for the moil; part entire ; ftrongly decurrent, fo as to render 

 the Hem winged. Flowers terminal, feflile, pale blue, foli- 

 tary, except occafionally on the molt luxuriant brandies. 



4. R. mufcofa. Mofly Roella. Linn. Suppl. 143. Willd. 



n. 4. Thunb. Prodr. 38 Leaves ovate, toothed, reflexed, 



fmooth. Flowers terminal, folitary. Stem herbaceous, dif- 

 fufe. — Gathered at the Cape by Thunberg. A very fmall 

 annual fpecies. 



5. R.fpicata. Spiked Roella. Linn. Suppl. 143. Willd. 

 n. 5. Thunb. Prodr. 38. — Leaves lanceolate, fringed, 

 nearly entire. Flowers terminal, fomewhat fpiked. Stem 

 fhrubby, ereft — Found by Thunberg at the Cape. We 

 have feen no fpecimen of this or the laft. 



Linnaeus, in Sp. PI. 241, has a R. reticulata, adopted 

 from Van Royen and Petiver, which appears to be no other 

 than his own Gorteria ci/iaris ; Cullumia ciliaris of Brown, 

 in Ait. Hort. Kew. v. 5. 137. 



ROEMER, Olaus, in Biography, a Danifh aftronomer 

 and mathematician, who flourilhed in the 17th and 1 8th 

 centuries, was born at Arhuffen, in Jutland, in the year 

 1644. From an elementary fchool at his native city he was 

 fent to the univerfity of Copenhagen, in 1662, where he dif- 

 tinguiflied himfelf by the progrefs which he made in his aca- 

 demical (Indies, and particularly in the mathematical fciences, 

 which were the favourite fubjeds of his purfuit. By dill— 

 j;< -nt ftudy he had, 111 167 1, become fo expert an aftronomer, 

 that, being introduced to M. Picard of the Academy ol 

 Sciences at Paris, who was lent by Louis XIV. to make 

 allronomical obfervations i.i tin- northern regions, he was 

 feleded to accompany him when In- returned to France. 

 1 lere lie prelented him to the king, who appointed him ma- 

 thematical preceptor to the dauphin, and fettled a penfion 

 upon him. Roeraer was united with Picard and Caflini in 

 making allronomical obi. 1 itions, ind 111 1672 he was ad- 

 mitted .1 member of the Royal Academy of Sciences at 

 Paris. He refided ten yean .11 Paris, and acquired a high 

 reputation by his many difcovei ie ., among which was iln 

 very import ant one by which he afcertamed the velocity 

 with which light moves, by meant of I he eelipfes of Jupi- 

 ter's fatellites. (See Lu;iir.) This difcovery was after- 

 Wards confirmed by Dr. Bradley. In 1681 Roemer was re- 

 called to his qwn country by Chriltian V. king of Denmark, 

 * 11 who 



