VOL. XI.] 



PHILOSOPHICAL TRANSACTIONS. 



349 



one full revolution of the hand on the index may answer the greatest shrinking 

 and swelling in the year, and the distance between the two rollers or pulleys 

 fixed on the axis must be the thickness of the pannels ; so that the weight is to 

 play or move on the one side of the pannel, and the chain on the other, with- 

 out disturbance or rubbing against the sides of the pannel or the cross, between 

 which, in the middle they are to be placed out of sight. 



The deal board should be of the iinest and straightest grained dram deal laid 

 to dry two or three years. And to know whether it be sufficiently seasoned, 

 take a small part of it, and weigh it in a nice pair of scales, and if you find the 

 weight not increased many grains in wet weather, nor decreased in dry, you 

 may then conclude it fit for your purpose. 



An Occultatlon of Mars hy the MooUj Sept. \, N. S. 1676, observed at Dantzic, 



by M. Hevelius. N° 129, p. 721. 



Mars was first covered by the moon about Mount Audus, thence proceeding 

 as it were through the Loca Paludosa of the moon, by Mount ^tna, below the 

 island Besbica, above the Pal us Acherusia, above Mount Corax, by the Palus 

 Maeotis, and a little above the isle Alopecia, and the very centre of the moon ; 

 and thence emerging at the great western lake. If it be asked how I could thus 

 exactly trace out the planet's passage behind the moon, and even that of her ob- 

 scure part; it proceeded from hence, that by those tubes of mine I could very 

 distinctly perceive the principal of the larger spots in the shaded part of the 

 moon ; so that I could observe very plainly, that Mars emerged near the middle 

 of Palus Maeotis. 



