205 



heard in the east, they expect hail and rain to follow* 

 Undoubtedly all these storms are owing to subterraneous^ 

 winds. To these likewise we may attribute the sudden 

 cracking of the ice upon the lake in the spring. This is 

 one minute strong enough to bear horses and sledges, 

 and the next broken in pieces. A strange noise under- 

 neath, which precedes 'the breach, warns travellers to 

 make the b*e^t of their way. But those who happen to 

 be at a great distance from land, are swallowed up, un- 

 less they can float upon shoals of ice, till they meet with 

 relief. The violent under currents observed in this lake 

 are also very surprising. These direcily opposing the 

 winds, give the fishermen a great deal of trouble. From 

 these, as well as from unfathomable depths, it is sup- 

 posed to have a communication under ground with 

 another lake called Venner, about forty miles^ to the 

 westward, 



13; It remains only to add a few reflections, on some 

 of the preceding heads. 



How useful is the atmosphere to the life, the health,, 

 the comfort, and the business of the whole globe ! It is 

 the air * by which all animals live : not only the inhabi- 



* As the air is of absolute necessity to animal life, so it is neces- 

 sary it should ^be of a clue consistence, not foul, for that suffocates ; 

 not too thin, for that suffices not. 



In the diving bell, after some time of stay under water, they are 

 forced to come up and take in fresh air. But Cornelius Drebell- 

 contrived not only a vessel to be rowed under water, but also a 

 liquor to be carried therein, that would supply the want of fresh 

 air. The vessel was made for King James the First. It carried 

 twelve rowers beside the passengers. It was tried in the Thames. 

 A person who was therein told it one who related it to Mr, Boyle. 

 As to the liquor, Mr. Boyle discovered ;by a physician, who married 

 Drebell's daughter, that from time to time, when the air in the sub- 

 marine boat was so clogged by the breath of the company, as to be- 

 unfit for respiration, by unstopping a vessel full of this, he speedily/ 

 restored it, so that they breathed again without difficulty. 



And as too gross, so too thin an air, is unfit for respiration* Hence, 

 the difficulty of breathing, (as all travellers relate) upon the top ofr 

 hi^h fountains. But the, cause of this difficulty is riot the, thin ness > 

 K. 6 



