i46 PHILOSOPHICAL TRANSACTIONS. [aNNO I6Q7 . 



For, first, It will not be practicable without a telescope. Secondly,- The ob- 

 server will always have opportunity, before his principal observation, to note the 

 distinction between the true shadow and the penumbra. And, thirdly. It will 

 be applicable to those seasons of the eclipse, when the alteration in the appear- 

 ances is most sudden. For which purpose, let a select number of the most 

 eminent spots, dispersed over the moon's surface, be pitched on to be con- 

 stantly used in all parts of the world ; as, for example, those which M. Heve- 

 lius calls Mons Sinai, ^tna, Porphyrites, Scrorum ; Insula Besbicus, Creta ; 

 Palus Mseotis, Maraeotis, and Lacus Niger Major. 



In each eclipse let, for instance, three of these spots, which then lie nearest 

 the ecliptic, be exactly observed, when they are first touched by the true sha- 

 dow, and again when they are just completely entered into it ; and also in the 

 decrease of the eclipse, when they are first fully clear from the true shadow; 

 for the accurate determinations of which moments of time, let there be taken 

 altitudes of remarkable fixed stars, on this side of the line, of such as lie be- 

 tween the equator and tropic of Cancer, but beyond the line, of such as are si- 

 tuated towards the other tropic ; and in all places of such as at the time of ob- 

 servation are about four hours distant from the meridian. 



Halos about the Moon. By the Earl of Sandjvich. N" 22, p. 390. 



December 25, old style, l666, in the evening there appeared at Madrid a 

 great halo about the moon, the semidiameter whereof was about 23 deg. 30m. 

 Aldebaran was exactly in the north-east part of the circle, and the two horns of 

 Aries were enclosed by the south-west of it, the moon being in the centre. 

 About five or six years ago, viz. November 21, l66l, an hour after sun-set, I 

 saw a great halo about the moon of the same semidiameter, at Tangier, the 

 moon being very near the same place where she was at the other observation. 



Toads and Spiders intioxious. By Dr. N. Fairfax. N° 22, p. 391. 



The ingenious author of this letter having taken notice of what was pub- 

 lished in Number g, viz. that creatures reputed venomous are indeed no poisons 

 when swallowed, though they may prove so when put into wounds ; he, for 

 confirmation thereof, alleges examples of several persons well known to him, 

 who have frequently swallowed spiders,* even of the rankest kind, without any 

 more harm than happens to hens, red-breasts, and other birds, who make spi- 



* It is certain that the generality of common spiders maybe swallowed with perfect impunity, the 

 extremely small quantity of the poisonous fluid with which their fangs are provided, being incapable 

 of injuring the larger animals. Several persons have been in the habit of making this idle experi- 

 ment : among others the famous Anna Maria Schurman is said to have had a propensity of this 



