PNEUMATICS. 



aor. 0wro, porf. pass. 00i<r>u, inf. /30wru, P**- 



'(l) afiK-M-OMa', / "'' '" ' ' fllt *{O/MU, aor. 2 ofJaoMn'. of.irot;, 

 afiKf<rflaj, perf. afiyncu, inf. px*". P la P- 

 a<j>i{o, eto. 

 (c) uirHrx-K'-oM"". J promwe, aor. fortifx-oM^ "P r ' 



fut. uwo<rx)<ro^ai, jwrf. tm<rxiM" i "w M*X" M' " r 

 I """' / '"N* <m ' ut - M^{M a *' * r - ** 

 and 



EXERCISE 123. GRKEK-ENOLISH. 

 1. Tots ffrpa-ftoncus tv rri ffrpartif iro\\a KO.KO, jW 



2. 



3E<Kf>cns <S|UiAa>f KCU oirroj K/3ij<nj <ro<>oj. 3. 

 {T)A.aff* TTJS 2irapT7jj. 4. IIoAAoi <ru/ti 

 <f>i\oi. 5. 'O /i0uj' BouAoj KTTI rou -KfiruKtvcu. 6. Owe (-io/xou 

 TOP (HVOC. 7. Tom icaKOVpyovs ol Of at airoTiffatVTO. 8. Ol iroAtTai 

 TOVS iroA.ffiouy t<J>0a<rai' fts rqv -KoKiv Qvyovrts. 9. 'O \ayus Into 

 rou KVVOS fSiJx^n- 1Q. Ovroi y' <fnTi TUV a.KfXii> avtv irovov. 11. 

 Ai yvvatKfs wxtffxorro (caAa ijuarta. 12. 'O oivos vwo rwv 

 13. 'O 



EXERCISE 124. ENGLISH-GREEK. 



1. The woman put on beautiful garments. 2. The woman 

 will put on beautiful garments. 3. The friends promised to 

 come. 4. The general got into the city before bis foes. 5. 

 The gods punish evil-doers. 6. Many friends drank together. 

 7. Friends drinking together become enemies. 8. Many evils 

 happened to my children as they came (coming) hither. 9. Oh 

 that Apollo would punish that evil-door ! 



KEY TO EXERCISES IN LESSONS IN GREEK. XL. 



EXERCISE 117. GREEK-ENGLISH. 



1. It is not easy to judge friends. 2. Wealth has often misled him 

 who has acquired it into a different habit of life. 3. The messenger 

 brought news of the victory. 4. The enemy ravaged the country. 5. 

 Pity shipwrecked men, since a voyage is uncertain. 6. If you kill 

 your foe you will pollute your hands. 7. I shall sow the fields, but 

 God will give the increase. 8. Do not reveal the secrets of a friend. 

 9. It is not easy to change an evil nature. 10. Chance has often 

 tripped up the proud unexpectedly. 



EXERCISE 118. ENGLISH-GREEK. 



1. Ol iraid>r ra? xeipar fjLiatvovaiv. 2. On oVvaToi* tan 4>iXoi/r xpivai. 3. 

 rioXXoi vita Titc aooXeax"" &teq>9aipnet>oi ttatv. 4. 'II vt*n <""> TMK a-jjt\V 

 eirt1Tjt\0n- 5. Ol a*faOot TOOT ircvn-rur oiKTfpovatv. 6. Ex Tnr <rr)t <^iripiar 

 woXXa ep3uar. 7. *i*oi <f>i\tt TU npi/irra ouic txipavolatv. 8. Ol itoXirui 

 Tar 7iac aitftpovatv. 



EXERCISE 119. GREEK-ENGLISH. 



1. The soldiers were encouraged for the fight by the general. 2. 

 Philip lost his sight by a wound in the eye from an arrow at the siege 

 of Methone. 3. The fruit of wisdom shall never be destroyed. 4. I 

 should be ashamed if I appeared to think more of my own glory than 

 the common safety. 5. Milo, the athlete of Croton, took up a bull, 

 and carried it through the midst of the race-course. 6. News had 

 been spread through the city that the enemy were conquered. 7. The 

 citizens will be avenged on the enemy for the defeat. 



EXERCISE 120. ENGLISH-GREEK. 



I. *O TpaTi!70t TOUC <rrpaTiTar fit Tn MX1 apuf vvtv. 2. Ol trrparrrfOi 

 i-our orpaTiuTjT wapofvvovoi*. 3. Ol woXiTai TOUV *o\tntom wepi -rnt hn 

 a^i'KOi'Tui. 4. El <roi>oofeic iravra rax< rpo>eir. 5. Uavra uw OUT 

 ir<pai'Tai on tawov&aCtv. 6. Ot ro\tfiioi ol otdnrap/jcvoi waX;i- favovvrc 

 7. A7a8or oXiTi)9 ^aXXo ^poi-Tifec TO HOIVOV i\ rou i-av-rov afaOo*. 8. 'Yo 

 mr inc irai-T*? ol ircXiTai tv^ooLoOncao. 9. 'H oX i-wo TOK to\f> 



DUMATICS. V. 



BABO1TITBB (eOlUtniMd) CPBIMOIL PUMP BKIOHT Or ATMO- 

 PUKBK BLAJTICITT OF AIU UOTLK AMD MAEIOmt't LAW. 



An then i* a difficulty in carrying an ordinary barometer from 

 place to place, Mveral special arrangement* have been planned 

 for the pnrpoM. An ordinary cistern barometer U often Mi- 

 ployed, in which the cistern U attached firmly to the end of the 

 babe, and made with leather sides, so that by turning the screw 

 at the bottom the tube U completely filled, and thus the risk of 

 breakage U much diminished. The tripod from which it hang* 

 is also to constructed M to form a safe oaee for the instrument 

 on the journey. 



Still, even the beet of these arrangements U heavy and awk- 

 ward to carry about, and therefore an entirely different kind of 

 barometer is usually employed for this purpoee. 



Till recently, barometer* containing liquid, whether mercury 

 or water, were universally employed, but now dry or solid 

 barometers are coming rapidly into use, on account of their 

 much greater portability. These are called aneroid barometers, 

 and consist of an exhausted chamber, the increase or diminution 

 of the pressure on which causes a slight variation in its size, 

 and the alteration being magnified by means of a series of 

 levers, moves the hand over a graduated dial-plate. 



In outward appearance the instrument closely resembles a 

 watch, and some are now made no larger than this, and may 

 therefore be easily and safely carried about in the pocket. 



The first mode of making these was with a flat circular box, 

 made of some elastic metal, and having the flat sidee corrugated, 

 to increase the elasticity. This pressed on one side against the 

 point of a screw, by means of which it could be adjusted so as to 

 correspond with the reading of a standard mercurial barometer. 

 The other side of the case was pressed upon by a small pointer, 

 attached to the shorter end of a lever, which moved the hand. 

 An improvement on this form was, however, effected by M. 

 Bourdon. He found that if a thin metallic tube be exhausted 

 and curved into a circular form, any increase of pressure on the 

 outside tends to curve it more, while a diminution of pressure 

 straightens it. A flat tube is accordingly taken, and, baring 

 been exhausted and hermetically sealed, it is curved round into 

 a circular form. Fine wires or cords pass from the ends to a 

 small lever on the axia of the needle, and thos, when the pres- 

 sure diminishes, the tube opens a little, drawing these wires, 

 and thus moving the hand on the dial-plate to one side. A 

 small spiral spring is also placed in the case, so that when the 

 pressure again increases, and the wires are slackened by the 

 tube curving, this may pull the hand back to its place. 



The chief practical difficulty in the construction of this in- 

 strument arose from want of elasticity in the tube. If it could 

 have been made of tempered steel it would have answered ; 

 this, however, was impracticable, but a flat spring placed inside 

 the tube is found to answer nearly as well, and aneroid baro- 

 meters can now be obtained so well made that, if they are oc- 

 casionally adjusted by a standard barometer, they will serve for 

 most purposes. 



There is another plan of ascertaining heights, which may be 

 mentioned here as being of easy application, and depending on 

 the pressure of the air. It is by means of a thermometer. If 

 we place a cup of warm water under the receiver of an air-pump 

 and exhaust the air, we shall soon find the water rapidly boiling, 

 even though its temperature is not higher than may be comfort- 

 ably borne by the hand. When a liquid is exposed to a source 

 of heat, the portions of it nearest the flame have a tendency to 

 assume the state of vapour, and they do this as soon as their 

 tension becomes eqoal to the pressure on the liquid. If, there- 

 fore, we diminish the pressure, a less tension will be required, 

 and therefore ebullition will ensue at a lower temperature. 



The temperature, then, at which ebullition ensues varies with 

 the pressure, and hence is an indication of it just as the height 

 of the column in the barometer is, and by means of tables con- 

 structed for the purpose we can tell the pressure from the tem- 

 perature at which water boils, and thus dednoe the height as 

 before. As a rough guide, it may be stated that each 600 feet 

 in elevation lowers the boiling point one degree on the Fahren- 

 heit scale. 



Another simple experiment, illustrating the fact of watet 

 boiling at a lower temperature if tho pressure be diminished. 



