

PNE 



will drive a bullet, with great violence, by 

 r.n ana of condensed air, forced in'.o an 

 iron oaii by a condenser. Fig. 11, repre- 

 sents the condenser tor forcing the air 

 into the ball. At the end of this instru- 

 ment is a male screw, on which the hol- 

 low ball, b, is screwed, in order to be fill- 

 ed with condensed air. In the inside of 

 this ball is a valve, to hinder the air, after 

 it is inje cted, from making its escape, un- 

 til it be forced open by a pin, against 

 which the hammer of the lock strikes ; 

 which then lets out as much air as will 

 drive a ball with considerable force to a 

 great distance. 



When you condense the air in the ball, 

 place your feet on the iron cross, h ft, to 

 which the piston-rod, d, is fixed ; then 

 lift off the barrel, e a, by the handles, i i, 

 until the end of the pision is brought be- 

 tween e andc; the barrel, a c, will then 

 be filled with air through the hole, e. 

 Then thrust down the barrel, a c, by the 

 handles, i i, until the piston, e, join with 

 the neck of the iron ball at a ; the air be- 

 ing thus condensed between e and a, will 

 fora open the valve in the ball, and when 

 the handles are lifted up again, the valve 

 wiii close and keep in the air, in this man- 

 ner the ball will presently be filled; after 

 which, unscrew the ball oiTthe condenser, 

 and screw it upon another male screw, 

 which is connected with the barrel, and 

 goes through the stock of the gun, as re- 

 presented, (fig. 12) The whole will be 

 better understood by (fig. 13.) which is a 

 section of the gun. The inside, h, is that 

 from which the bullets are shot, and, 

 C D S R, is a larger barrel. In the stock 

 of the gun, M, which forces the air 

 through the valve E P, into the cavity be- 

 tween the two barrels, th<jre is a valve 

 atSL, which being opened by the trig- 

 ger, O, permits the air to rush suddenly 

 behind the bullet, so as to drive it out 

 with great force. If the valve is sudden- 

 ly opened and closed, one charge of con- 

 densed air may make several discharges 

 of bullets. 



PNEUMORA, in natural history, a ge- 

 nus of insects of the order Hemiptera. 

 Body ovate, inflated, diaphanous ; head in- 

 flected, armed with jaws ; thorax convex, 

 cannate beneath ; wing-cases deflected, 

 niembranaceous ; legs formed for run- 

 ning. There are only three species, viz. 

 1. P. immaculata: green spotted with 

 white ; wing-cases immaculate. 2. P. ma- 

 culata: wing-cases green, with square 

 white spots. And, 3. P. guttata : wing- 

 cases green, with two white spots ; abdo- 

 men with three white spots on each side, 



POE 



They are all found at the Cape of Good 

 Hope. The insects of this genus appear 

 to consist of a mere hollow inflated mem- 

 brane : by rubbing together their sen-ate, 

 or toothed leg*, they make a shrill kind 

 of noise morning and evening, and follow 

 a light ; and they are so nearly allied to 

 the cnckc t tribe, that they have been enu- 

 merated by some naturalists under the 

 genus Gryilus. 



PDA, in botany, meadow-grass, a genus 

 of the Triandria Diyy rua class and order. 

 Natural order of Gramma, or Grasses. 

 Essemial character: calyx two-vailed, 

 many-flowered: spikelet ovate; valves 

 scariose at the edge, and sharpish. There 

 are seventy one species. 



POCKET, in the woollen trade, a word 

 used io denote a large sort of bag, in 

 which wool is packed up to be sent from 

 one part of the kingdom to an another. 

 The pocket contains usually twenty-five 

 hundred \wight of wool. 



PODOPUYLLUM, in botany, a genus 

 of thi Polyandria Alonogynia class and 

 order. Natural order of iihoeadeae. Ra- 

 nunculaceze, Jussieu. Essential charac- 

 ter : calyx three-leaved; corolla nine- 

 petalled ; berry one-celled, crowned with 

 the stigma. There are two species, viz. 

 P. peltaium, duck's-foot, or May-apple ; 

 and P. diphyllum. 



PODU11A, in natural history, spring tail, 

 a genus ot insects of the order Apiera. 

 Generic character : lip bifid ; four feelers, 

 subclavate; two eyes, composed of eight 

 facets ; antennae filiform ; body scaly ; 

 tail forked, bent under the body, and 

 acting as a spring, hence its name ; six 

 legs, formed for running. There are thir- 

 ty-one species. They feed on leaves of 

 various plants : the larva and pupa are 

 six-looted, nimble, and resemble the per- 

 fect insect. P. aquatica is black, and, as 

 its name imports, aquatic ; they assemble 

 in troops early in the morning, on the 

 banks of pools and fish-ponds. P. ambu- 

 lans is white, with a bifid extended tail, 

 and is found principally among moss. 



POETICAL rising and setting of the 

 stars. The three kinds of rising and set- 

 ting, viz. the cosmical, acronical, and he- 

 liacal, were made by the ancient poets, 

 referring the rising, &c. of the stars to 

 that of the sun. 



POETRY. Dr. Blackwall, in his Es- 

 say on the Life and Writings of Homer,'* 

 says, on the subject of poetry, that " it is 

 of a nature so delicate, as not to admit of 

 a direct definition; for if ever ihejene 

 scats quoi was rightly applied, it is to the 

 powers of poetry, and the faculty that 



