1826.] Telescopical Observations on the Moon, 339 



sions were less satisfactory, because the star was eclipsed during 

 a considerably longer time ; it touched the dark part of the 

 globe near the north horn ; before it was quite in contact, it was 

 elongated in a direction perpendicular to a tangent at the point 

 of contact ; it lost a sensible part of its brilliancy before it dis- 

 appeared. Should a total ecHpse happen, when the moon is 

 near the meridian, and in the milky way, or any crowded part of 

 the heavens, occultations of every sort, and very close appulses, 

 might be observed, whereby the question may be decided. 



Results of a rather satisfactory nature were obtained from the 

 occultation of Saturn, Oct. 30, 1825. At the immersion, the 

 moon's altitude being very low, the wind high, and the air very 

 tremulous, a good observation could not be made. The emer- 

 sion happened under better circumstances ; it took place from 

 behind the dark part of the disc ; and when a very minute part 

 of the Wansa first appeared, it was very considerably agitated ; 

 whilst some minute insulated specks on the dark part of the 

 moon were quite steady, and in the field of view at the same 

 time. As more of the ring came into view, the part which was 

 very near the moon was indistinct ; and when the globe of the 

 planet had emerged, and a vacant space of two or three seconds 

 of a degree between it and the moon ought to have been seen, 

 the globe of Saturn was extended to the moon's limb, and indis- 

 tinct on part of that hemisphere ; and as the remainder of the 

 ring emerged, the part near the moon was confused and indis- 

 tinct, whilst the remote parts were distinct and well defined. 

 The observation was made with a six inch Newtonian reflector, 

 power 130; a higher could not be used on account of the unfa- 

 vourable state of the air. Saturn's light being inflected by 

 passing by the moon's surface, some part of the appearance 

 must have resulted therefrom ; and although it is difficult, or 

 rather impossible to calculate the effect due to inflexion, yet, 

 reasoning from analogy, the effects appear too considerable to 

 be the effect of inflection alone. 



We may now examine how far observation supports the idea 

 that there are seas in the moon. There is certainly one great 

 difficulty, although some of those parts which are supposed to 

 be seas are favourably situated, the reflected image of the sun 

 has never been observed. However if the moon be similarly 

 constituted to the earth, the surface of the sea will rarely be 

 smooth ; and whether the trifling quantity of light reflected 

 from the surface of water, even if smooth, would be visible at so 

 great a distance as 240,000 miles, is doubtful ; and if rough, 

 undoubtedly its dissipation must be so great that the sun's 

 image cannot be visible on the earth. If parts of the moon be 

 covered with water, they will appear darker than the other parts 

 of the surface, except in that point which reflects an image of 

 the sun, if such there be ; for, excepting at that point which 

 must be very small, none of the reflected rays can reach the eye 



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