VOL. XXXVI.j PHILOSOPHICAL TKANSACTIONS. 3(17 



dried the sponge, which then weighed but l6\ grains, and having applied it to 

 the damp for the space of 10 ininutes, found again, that it had not gained the 

 least part that could be perceived in its weight. Also, a large bundle of catgut, 

 weighing 2 oz. 15dwt. 10 gr. acquired not the least augmentation, by being 

 suspended for a very considerable time. 



To these experiments he added one on the hydrostatical balance, to deter- 

 mine whether there was any extraordinary difference as to the density, or spe- 

 cific gravity of common, and this vitiated air. The balance was very large, 

 and accurately poised, and the solid, which was a globe, was 4-,^ inches in dia- 

 meter. This with its string weighed in the air 7 oz. 6dwt. And after being 

 immersed in the damp, it lost nothing of its weight, being then in equilibrio to so 

 great a degree of exactness, that -^ a grain would over-ponderate on either side. 



This damp abated more and more by being exposed to the air, till on July 

 the ISth, persons were let down to the bottom without any inconvenience. 



The other instance is of a very sudden subterraneous vapour, on May g, 

 1729, in a well in School-house-street, Boston. This well had been opened 

 for some considerable time, and not only enlarged in its diameter, but sunk 14 

 or 1 5 feet deeper. Two men undertook to lay the stones. They had been em- 

 ployed all the day, till about 6 o'clock in the afternoon, when one perceived a 

 very unusual stench, and by the extraordinary increase, he was apprehensive of 

 some great danger. The other was hitherto insensible of it, but perceiving his 

 partner's visage to change in a very uncommon degree, called up for relief; at 

 which instant, as he afterwards expressed himself, he first perceived a very 

 strong noisome smell, resembling rotten fish, which on a sudden seized his 

 senses, and rendered him unable to sustain his weight. The first had immedi- 

 ately closed his mouth and nostrils with his hand; and when the bucket was 

 lowered with a third person for their relief, assisted in getting the second into 

 it. As the bucket was raising, the latter was taken with very unusual and ex- 

 traordinary fits; and when he was laid on the ground, till the first was taken 

 out, could scarcely be kept still by the united strength of 3 or 4 persons ; but 

 bounding and writhing his body, like a fish newly taken from the water. The 

 first was affected only with fainting fits. After 3 hours the '2d recovered of 

 these extraordinary convulsions, but was disordered in his brain during the 

 whole night: and though the former was sooner relieved of his fits, he con- 

 tinued extremely disordered for a longer time. It was thought remarkable, 

 that neither of them was affected with either vomiting or purging. 



This accident happened on Friday, and on the Monday tiiey were both 

 restored to perfect health. The well continued infected for a very little while, 

 and when on the Monday following some other workmen renewed the work, 

 there was nothing noisome that could be perceived. 



