Page:On the various forces of nature and their relations to each other.djvu/86

82 would you propose to me if, having lost the stopper out of this alcohol bottle, I should want to close it speedily with something near at hand. Well, a bit of paper would not do, but a piece of linen cloth would, or some of this cotton wool which I have here. I will put a tuft of it into the neck of the alcohol bottle, and you see, when I turn it upside down, that it is perfectly well stoppered, so far as the alcohol is concerned; the air can pass through, but the alcohol cannot. And if I were to take an oil vessel, this plan would do equally well, for in former times they used to send us oil from Italy in flasks stoppered only with cotton wool (at the present time the cotton is put in after the oil has arrived here, but formerly it used to be sent so stoppered). Now, if it were not for the particles of liquid cohering together, this alcohol would run