542 PHILOSOPHICAL TRANSACTIONS. [aNNO I67O. 



frequently soever we made such observations, we never could so hit it as to see 

 even the least vein of frost, but always it was either all fluid or all frozen. 

 Whence we conjectured, that the work of congelation was done in a very short 

 time, and that he who should have the luck to take the globe out of the ice in 

 that nick of time when the water should receive so sudden a change, would cer- 

 tainly find something very notable thereby. And because by the so often taking 

 out and putting the globe into the ice, the whole period of its changes was dis- 

 ordered ; we let it return to just the same mark as it was at first, and then 

 placing it into the ice, we fixed it to that degree in which it was wont to take 

 that very impetuous motion, and half a degree before it arrived at it, we took 

 it out. Then looking carefully on the water in the globe, which by reason of 

 the transparency of the crystal was plainly seen to be yet altogether fluid and 

 clear, the water, though now out of the ice, did by the operation of the intro- 

 duced cold (after it had attained to its due point with a swiftness imperceptible 

 to the eye, the transparency within the globular part being lost, and itself in an 

 instant, as it were, deprived of its motion) totally conglaciate. Which experi- 

 ment we tried over and over again, and found it always succeed alike. 



A7i Eclipse of the Moon; a Conjimction of Venus and the Moon, &c. By 

 M. Hevelius. Translated from the Latin. N" 66, p. 2023. 



Sept. 29, 1670, in the morning, the beginning of the moon's eclipse was 

 about 2 hours 11 minutes; though it could not be very accurately observed, on 

 account of the earth's shadow being very faint; for during the whole eclipse, 

 the shadow was so thin and dilute, that all the principal spots could be seen 

 through it with a telescope of 20 feet, and even a shorter. The greatest ob- 

 scuration was about 3h. 50m. the end of the eclipse was at 5h. 21 m. the whole 

 duration therefore was 2h. 59m. and the quantity of it was scarce more than 

 9 digits. 



According to Riccioli's tables. 



h. m. sec 



According to the Rudolphin tables. 



h, m. sec. 



The beginning 2 37 5 



Greatest obscuration 4 2 50 



The end 5 28 35 



Whole duration 2 5 1 30 



Quantity of digits 9 4 O 



The beginning 2 14 47 



Greatest obscuration 3 55 37 



The end 5 36 27 



Whole duration 3 21 40 



Quantity of digits 11 43 O 



About the middle of this eclipse, at 3 h. 40 m. I clearly observed an un- 

 known telescopic star, covered by the moon near the lacus niger major. After 



