468 PHILOSOPHICAL TRANSACTIONS. [aNNO 1747-8. 



he endeavoured last summer to find out by experiment. J st, Whether sound 

 made in the open air can be heard by a land animal immerged under water. 2d, 

 Whether, and in what manner, sound made under water can be heard by a land 

 animal in the open air. And, 3d, Whether, and in what manner, sound made 

 under water can be heard by a land animal that is likewise under water. 



To satisfy his first inquiry, whether sound made in the open air can be heard 

 by a land animal under water; he caused 3 people, stripped quite naked, to dive 

 down at the same time, and to remain about 2 feet below the surface of the 

 water, in which situation he spoke to them as loud as he was able. At their 

 coming above water, they repeated his very words, but said he spoke very low. 

 He caused the same persons afterwards to dive down about 1 2 feet under water, 

 and a gun was discharged over them, which they all said they heard, but that 

 the noise was scarcely perceivable. 



As to the second inquiry, whether, and in what manner, sound made under 

 water can be heard in the open air; he caused a young man to dive some feet 

 down, and then to endeavour to halloo, which he did ; and he could hear him, 

 though very faintly. But imagining the sound might come up with the water 

 he discharged at his mouth while he hallooed, he contrived a kind of hand-gra- 

 nado, which he threw into a place in the river about Q feet deep. The fuzee 

 burnt under water near 10 seconds, and then the granado went off, giving a 

 prodigious hollow sound, and shaking the adjacent ground to such a degree, that 

 the whole of a large building, some yards distant from the explosion, was put 

 into a tremor, far beyond what could be expected from so small a quantity of 

 powder. 



He satisfied his third inquiry, whether, ^nd in what manner, sound made 

 under water can be heard by a land animal that is likewise under water, by pro- 

 curing a young man to dive down with a bell in his hand; and he assured him, 

 that he heard its tinkling very distinctly, at all depths under water, with little or 

 no difference from what he did when rung in the open air; he likewise affirmed, 

 that he plainly heard the noise and rushing of the water, which came violently 

 through a flood-gate, about 20 feet distant from the place he was then in. 



The Substance of some Experiments of Planting Seeds in Moss, lately made by 

 Mr. Charles Bonnet* of Geneva, F. R.S. N" 486, p. 156. 



Mr. Bonnet was inclined to try whether plants were capable of vegetation, 

 when they were only set in moss, instead of being planted in the earth. With 



* Charles Bonnet was a celebrated naturalist of Geneva, where he was born in 1720. Very early 

 he applied to the study of natural history, and particularly to the study of insects, his first knowledge 

 of which he received from the works of Reaumur. He was indefatigable in his inquiries into the 

 habits and generation of that tribe of insects termed in French puceions, in English tree lice. lo 



