NO. 5. 



THE farmers' cabinet. 



/ / 



perfect splioie, its equatorial* diameter ex- 

 ceeding in Icngtii its axis by more than tiiirty 

 miles; the former being 7904 miles, and the 

 latter about 7930 ; her distance from the Sun 

 is 1)5,17;3,()0() miles; and siie traverses the 

 wliole of her orbit, in oGo days, hours, 9 

 miimtes, whicli constitutes her year. 



The axis of the Eartii is not perpendicular 

 to the plane of the Ecliptic,\ but inclined to 

 it at an angle of 32° 28 ; round this axis she 

 revolves in 23 iioiirs, 50 minutes, 4 seconds, 

 whicii is the length of the astronomical day. 



The inclination of the Earth's axis is the 

 principal cause of the variety or change of 

 seasons ; for as the axis of tlie Harth always 

 preserves its parallelism, in her revolution 

 round the Sim, at one part of her orbit she 

 receives most of tlie ligiit and heat on her 

 nortiiern hemisphere, and at another part on 

 her southern, according as her north or south 

 pole is turned towards the sun ; while in two 

 points of her orbit, botli iiemispheres are 

 equally enlightened. The accampanging dia- 

 gram will best explain the cause of the change 

 of seasons, and of the lengths of the days and 

 nights. 



Let A, B, C, D, represent the Earth in 

 four different parts of her orbit, equi-distant 

 from one anotlior ; — N for ajcis and the north 

 jmle, and S the sun, nearly in the centre of 

 the Earllis orbit. As the Earth goes round 

 the sun, according to the order of the letters 

 A, B, C, D, lier axis N keeps the same obli- 

 quity, and is exactly parallel in every part of 

 her orbit. 



When the Earth is at A, its north pole in- 

 clines towards the sun, and brings all the 

 northern" places more into the light tlian at 

 any other time of the year. But when the 

 Earth is at C, in the opposite time of the 

 year, the north pole declines from the sun, 

 which occasions tlie northern places to be 

 more dark than in the light, and the reverse 

 at tiie southern places. 



When the Earth is either at B or D, she 

 inclines not either to ox from the sun, but lies 

 sideways to him, and tiien the poles are in 

 the boundary of light and darkness ; and the 

 sun being directly over 'tiie equator, makes 

 equal day and night at all places. 



When the Earth is at E, it is half way be- 

 Icen the summer solsticeX and autumnal 



' Equatorial,belonging to tlie equator, an imaginary 

 lino whicli divides tlie world into two equal parts, called 

 the Northern and Siiutliern Iiemispheres. When the 

 s Ml ci'ines to tliis circle, the days and nights are equal 

 all round the globe. 



t The Ecliptic is a greater circle of the sphere, in which 

 the Sun always appears to move ; so called because 

 Kclipses generally happen when the Moon is in or near 

 this circle. It is divided into twelve equal parts, which 

 arecalled signs ; each of which takes its name from that 

 constellation which, at the time the names were given, 

 was situated near the portion of the Ecliptic it denomi- 

 nates. 



\ Is that time when the sun is at the greatest distance 



equinox; and wlien it is nt F, it is lialf way 

 betweea the auluninui c<iiiinox andliic loinlcr 

 sohtice ; at G, halfway I'roiii the winter sol- 

 slice to the spring equinox ; and at 11, half 

 way from the spring equinox to the summer 

 solstice. 



From litis it is cvidert, tliat when tiie 

 Earth is at A, the north pole is enligiitcned, 

 and \.\\G southern in darkness, and that exactly 

 the reverse is tiie case wlien the Earth 

 arrives atC,furtiiPn the south pole 'm enlight- 

 ened and tlie north in darkness; in the former 

 case, the northern hemisphere has summer 

 and the longest day, while tlie south has 

 winter and the shortest day ; in the latter 

 every thing is completely reversed. 



That the Earth is of a globular form, may 

 be inferred from analogy; as all the other 

 heavenly bodies which are visible to us arc 

 globes, there is little reason to doubt tiiat the 

 earth is so likewise. Of this, however, there 

 are demonstrative proofs. 



The motion of the Earth in her orbit round 

 the sun is called her annual motion, and tliat 

 round her axis, her diurnal 7notion, which, s.t 

 the equator, is about 1042 miles an hour. 



These two motions, although constantly 

 carried on together, are not sensible to us 

 because they are so equable, interrupted by 

 no impediments, and because every thing on 

 the Earth's surface, and the atmosphere itself, 

 partake of these motions. 



The Earth is surrounded by a compound 

 fluid substance called the atmosphere, which 

 consists of air mingled with aqueous vapours* 

 and other exhalations from her surface. This 

 atmosphere has a refractive^ power, by which 

 the rays of the sun are bent out of a straight 

 line, and occasion a degree of light after that 

 luminary is below the horizon. This faint 

 light is denominated tivilight. 



It has already been observed, that the Orbit 

 of the Earth is not a perfect circle, but in- 

 clined to the Elipse, and that the Sun is not 

 exactly in its centre. This occasions the 

 Earth to be seven days longer in passing 

 through one half of her orbit than she is in 

 traversing the other. The Orbit of the Earth 

 is placed between those of Venus and Mars. 



from the equator, and is thus called because he Ilien 

 appears to stand still, and not to change his distance ' 

 from the equator for some time, which appearance is 

 owing to the obliquity of our sphere, and which those 

 livins under the equator are strangers to. Solstice is 

 Irom the Latin words sol, sun, sto, to stand. 



* Jiqucoits vapours, watery particles. (Aqueous, 

 watery :— vapour, a particle.— Vii pour, a steam, a fume; 

 — a vain imagination.) 



t Frfrnclivc—havi-ng the power ofrefraction. Refrac- 

 tion is the deviation of a moving body from its direct 

 course, occasioned by the difJerent density of the medium 

 it moves in ; or, it is a change of direction occasioned 

 by a body's falling obliquely out of one medium into 

 another of a diflcrent density. 



