urmoiM 



ASTRINGENTS. 



Brlik 



Flora . 

 Euro pa 

 Kurtuiu 

 Euterpe . 



At 



\- ; >,.T:-. 

 Thalia 

 Lut*tia . 



!. ;.. 



N 



Pallas 



Euphrosyne 

 Cere* . 

 Vesta . 

 Hebe . 

 Proserpine 

 Polyhymnia 

 Leda 



Parthenope 

 Alexandra 

 Eugenia . 



The asteroids, Iris, Hygeia, Egeria, Thetis, Phocea, Urania, Pomona, 

 Leueothea, Lxtitia, Ariadne, Nyaa, Aglaja, Doris, and Pandora do not 

 come to opposition in 1859. The asteroid @ which is not included 

 in the list from which the foregoing numbers are extracted, may be 

 stated to be about the KHIUi magnitude when it comes to opposition. 



Since the asteroids exhibit no appreciable discs by the measurement 

 of which their absolute diameters might be determined, as in the case 

 of the other planets, astronomers have endeavoured to accomplish the 

 same object by means of photometric results, founded on their 

 apparent brightness, combined with an assumption relative to their 

 power of reflecting tie solar light. Professor Stampfer, of Vienna, has 

 endeavoured in this way to determine the absolute magnitudes of 

 several of the asteroids. By photometric experiments he found that 

 the planets Mercury, Venus, and Jupiter, possess the same capacity for 

 reflecting the solar light. By extending this principle to the asteroids, 

 the following results have been obtained (Bruhns, 'IV Planetis 

 Minoribus,' Berlin, 1856) relative to the absolute magnitude of those 

 i. -li. -. 



form some opinion on the subject, for the zone In which they perform 

 thoir revolution* contain* only a definite number of stars of the average 

 apparent magnitude of those bodies. But the more the search for new 

 Mteroid* i* prosecuted and the greater their aggregate number becomes, 

 UM smaller the more recently-discovered ones tuin out to be, and the 

 obvious inference therefore is, that there probably exist many more of 

 such bwUcn, which from their minute magnitude have hitherto escaped 

 detection. 



But it it is impontblo to assign any limit to the number of the 

 aoteroids, the result is different when we consider their aggregate 

 mas*. In thi* case it may be ascertained by calculations founded on 

 the theory of gravitation, that if the quantity of matter contained in 

 the totality of those bodle* exceeded a certain amount, tiieir attractive 

 force could not fail to produce sensible perturbation* in the movement* 



of the neighbouring planete Man and the earth. M. le Verrier baa 

 considered the subject from this point of view. His researches are 

 founded on UM twenty-nix asteroids which had been hitherto dis- 

 covered, but the conclusion at which he arrived is equally applicable 

 in UM present day. He found that if the aggregate mass f the 

 asteroids wa* equal to the earth'* mass, it* attraction would disturb 

 the place of the perihelion of Man to the extent of 11" in a century. 

 Now, if there really existed from such a cause a variation in the peri- 

 helion of the planet, amounting to even the fourth part of thi* quan- 

 tity, it could not escape observation in the present advanced state of 

 practical astronomy. The conclusion therefore is that the aggregate 

 of the asteroids doe* not amount to one-fourth of the earth's 



ASTHMA. [BRONCHITIS.] 



ASTRAOAL, a moulding used in architecture, and applied princi- 

 pally to the upper ends of the shafts of columns and to their base*. 

 It is also used in the entablatures of the Roman Doric, the I-ni.-. 

 Corinthian, and Composite orders. The term i* derived from the 

 Oreek iarpdyaXos, which signifies the bone on which the tibia rest*, 

 and sometimes a vertebra. The form of this moulding is semicircular, 

 projecting from a vertical diameter. The surface is usually worked 

 plain, although there are Roman examples of its being carved to repre- 

 sent leaves, as in the arch of the goldsmiths at Rome, or reeds bound 

 together, as in the pedestal of Trajan's column. The astragal cut into 

 bead* is common to Oreek and Roman architecture. 



Sections of astragal moulding*, and elevations of astragal mouldings cai v, d : 

 a, section of an astragal form the three columns of the temple of Jupiter 

 [Stator], in the Campo Vaccino, at Rome ; b, astragal used in the base of 

 the lonio order of the temple of Minerva Polios at Priono ; e, enriched 

 astragal used in the arch of the goldsmiths at Rome ; d, enriched astragal 

 of the pedestal of Trajan's column at Koine ; e, astragal cut into beads. 



The apparent use of the astragal is, to bind the parts of columns 

 and entablatures together, for which purpose it is employed Ixith at 

 the top of the shaft where the capital commences, and at the bottom 

 where the base terminates. Many of the parts also of the entablature 

 are bound together with the astragal moulding. 



In Egyptian architecture, bands curved after the manner of astragal* 

 seem to bind the reeds of which the shaft of the column often appears 

 to be formed. In the choragic monument of LysicrateB at Athens, 

 supposed to be one of the oldest examples of the Corinthian order, it 

 has been conjectured that the hollow between the top of the shaft ;m.l 

 the lower part of the capital of the column formerly received a I 

 ring of the form of an astragal, by which means, if the conjecture be 

 well founded, the parts, from the contrast of colour, would appear to 

 be more <liti*ctly bound together. The most remarkable example of 

 the use of the astragal in Grecian architecture is in the base employe! 

 in the Ionic temple of Minerva Poliaa at Priene ; which has been 

 imitated by Mr. Cockerell in the portico in the front of Hanover 

 Chapel, Regent-street. In the temple of Jupiter Olympius, at Athens. 

 the astragal at the top of the column appears to have a chanm-1 rut 

 underneath it (Stuart, vol. iii.) This, however, is very unusual. 

 [COLUMN.] 



ASTREA, one of the group of small planets revolving between 

 Man and Jupiter. [ASTEROIDS.] 



ASTRINGENTS (from futringo, to oonstringe, or bring closer 

 together) are agents wlii. h contract the fibres of the muscles and 

 blood-vessels, and lessen the flow of fluids, whether it be the 

 secretions of the glands proceeding from their natural orifices in exces- 

 sive quantity, or the contents of the blood-vessels escaping by their 

 exhalent extremities, or by on unnatural opening (or rupture). They 

 produce this effect, generally by a vital, but sometimes by :> < i 

 aeticiii. Their power is manifested first, and often solely, on the part 

 to which they are applied : vet in many instances it is extended l>y 

 sympathy very rapidly over the whole body, as is observed when tin 

 aeei-li juice of the sloe is brought in contact with the tongue. The 

 sensation then experienced may be considered the best general tost of 

 the presence of tutringeitfy, which cannot be ascribed to any one prin- 



