APO 



APO 



its flat side towards the object, and a 

 meniscus of the same materials, with its 

 convex side in the same direction, and its 

 flatter concave next the eye, and the in- 

 terval between these lenses he filled with 

 a solution of antimony in a certain pro- 

 portion of muriatic acid. The lens thus 

 adapted did not manifest the slightest 

 vestige of any extraneous colour. He 

 obtained a patent for the invention in 

 1791. 



APLUDA, in botany, a genus of the 

 Polygamia Monoecia class of plants, the 

 common calyx of which is an univalve, 

 bifloral, ovated, concave, loose mucrona- 

 ted glume; the proper glume is bivalve, 

 and placed obliquely; the corolla is a bi- 

 valve glume of the length of the cup; 

 there is no pericnrp'mm ; the seed, which 

 is single, is involved in the glume of the 

 corolla. Male corol. two valved ; female 

 floret sessile ; stamina three. Female 

 corol. two valved; one style; one seed, 

 covered. There are four species. 



APOCOPE, among grammarians, a fi- 

 gure which cuts oft a letter or syllable 

 from the end of a word, as ingeni for in- 

 genii. 



APOCRYPHAL, something dubious, 

 is more particularly applied to certain 

 books notadmitted into the canon of scrip- 

 ture. Those arc certain books of the Old 

 Testament extant only in Greek, admitted 

 by the church of Rome as canonical, but 

 rejected by the reformed churches as no 

 part of holy writ; such are the books of 

 Judith, ^Visdom, .Tobit, Baruch, Macca- 

 bees, the third and fourth books of Es- 

 dras. In this sense apocryphal stands 

 distinguished from canonical, though the 

 Romish church disowns the distinction. 

 Authors are divided as 1o the origin of 

 the appellation apocryphal, and the rea- 

 son why it was given to these books. 

 The apocryphal books were not received 

 into the canon, either of the Jews, or an- 

 cient Christians, but were first made ca- 

 nonical by a decree of the council of 

 Trent The apocryphal books, accord- 

 ing to the sixth article of the church of 

 England, are to be read for example of 

 life and instruction of manners ; but it 

 doth not apply them to establish any doc- 

 trine. 



APOCYNUM, in botany, a genus of 

 the Pentandria Dvginia class and order. 

 Corol. ccnnpanulate ; nectareous filaments 

 five, alternating with the stamina. There 

 are 14 species. 



APODES, the name of one of the or- 

 ders of fishes in the Linnaean distribution 

 of animals. Their character is, that they 



have no belly fins ; there are 12 genera, 

 viz. 



Ammodytes, Ophydium, 



Anarhichas, Sternoptyx, 



Gymnothorax, Stomateus, 



Gymnotus, Stylephorus, 



Leptocephalus, Trichiurus, 



Mursena, Xiphias, 



which see under the several heads in the 

 alphabet. 



APOGEE, in astronomy, that point of 

 the orbit of a planet, or the sun, which is 

 farthest from the earth. 



Ancient astronomy, which placed the 

 earth in the centre of the system, was 

 much taken up in ascertaining the apogee 

 and perigee ; which the moderns have 

 changed for aphelium and pcrihelium. 

 See the article AniKLifM, 8cc. 



APOLLONIUS, of Perga, a city in 

 Pamphilia, was a celebrated geometrician, 

 who flourished in the reign of Ptolemy 

 Euergetes, about 240 years before Christ; 

 being about 60 years after Euclid, and 30 

 years later than Archimedes. He studied 

 a longtime in Alexandria under the disci- 

 ples of Euclid ; and afterwards he com- 

 posed several curious and ingenious geo- 

 metrical works, of which only his books 

 of Conic Sections are now extant, and 

 even these not perfect. For it appears 

 from the author's dedicatory epistle to 

 Eudemus, a geometrician in Pergamus, 

 that this work consisted of eight books ; 

 only seven of which however has come 

 down to us. 



From the Collections of Papus, and 

 the Commentaries of Eutocius, it appears 

 that Apollonius was the author of various 

 pieces in geometry, on account of which 

 fie acquired the title of the great geome- 

 trician. His Conies was the principal of 

 them. Some have thought that Apollo- 

 nius appropriated the writings and disco- 

 veries of Archimedes; Heraclius, who 

 wrote the life of Archimedes, affirms it ; 

 though Eutocius endeavours to refute 

 him. Although it should be allowed a 

 groundless supposition, that Archimedes 

 wasthe first who wrote upon conies, not- 

 withstanding his treatise on conies was 

 greatly esteemed, yet it is highly proba- 

 ble that Apollonius would avail himself of 

 the writings of that author, as well as 

 others who had gone before him ; and, 

 upon the whole, he is allowed the honour 

 of explaining a difficult subject better 

 than had been done before, having made 

 several improvements, both in Archime- 

 des's problems, and in Euclid. His work 

 upon conies was doubtless the most per- 

 fect of the kind among the ancients, and 



