ANNUAL OF SCIENTIFIC DISCOVERY. 



tween these diverse particles, causing to the saturated air a charac- 

 ter of humidity. This character he believes to be imparted to the air 

 by actual contact only with the source of vapor, and not by any trans- 

 fer of the particles of vapor among the particles of air. 



NEW FACTS IN EEGARD TO SOAP-BUBBLES. 



In a recent communication to the French Academy, M. Felix Pla- 

 teau, the younger, states that having been requested by his father to 

 throw away a liquid of a bad quality which had been employed to 

 produce films, he endeavored to make it form a sheet of liquid in its 

 descent, when to his surprise it took on the shape of a large bubble, 

 and fell slowly. He repeated the experiment a good many times with 

 soap-suds, and sometimes succeeded in making as many as fifteen 

 bubbles at a time. He recommends a hemispherical vessel about five 

 inches diameter, holding a considerable quantity of the fluid, which 

 should be thrown at an angle of forty-five degrees with the horizon, 

 and have a spinning motion communicated to it. "In this exper- 

 iment," says M. Plateau, " my father sees an argument in support of the 

 vesicular state of the vapors in clouds. In fact, one of the principal 

 objections urged against tin's hypothesis consists in the impossibility 

 of conceiving how the molecules of the vapor could, whilst it was 

 passing to the liquid state, aggregate together so as to form envel- 

 opes enclosing air. Now, we see that such an aggregation in closed 

 envelopes is not immediately necessary ; it is sufficient that the mole- 

 cules of water should unite in open sheets of any figures and curva- 

 tures ; each of these lamellaa will immediately close so as to give rise 

 to a vesicle. Doubtless the character of these lamellce is itself not 

 easily conceived; but it appears at least much more admissible than 

 the entire formation of the vesicles." 



At a recent meeting of the Royal Society, London, Dr. Frankland 

 exhibited a series of very beautiful experiments devised by M. Pla- 

 teau, designed to show the optical and mechanical properties of thin 

 films. The films are obtained by means of a solution of one part of 

 pure oleate of soda in fifty of water; three parts of this solution 

 are then mixed with two parts of glycerine. The liquid thus obtained 

 is capable of being blown, by means of a common tobacco-pipe, into 

 bubbles of a very large size and great permanency. Dr. Frankland 

 stated that he had succeeded, by means of a blow-pipe bellows, in 

 obtaining a bubble nearly nineteen inches in diameter. When in- 

 flated with air these bubbles often last more than twenty-four hours ; 

 but when the^reath is employed, the oleate of soda is slowly acted 

 on by the carbonic acid expired, and their duration is limited to three 

 or four hours. 



A series of these bubbles, about six inches in diameter, were 

 placed on a number of glass rings situated in a line, and on a ray of 

 light from the electric lamp being transmitted through the series, 

 their beautiful iridescent colors were developed in the most magnifi- 

 cent manner. 



Other bubbles were inflated with a mixture of eight parts of air 

 and one part of coal gas, which, -by overcoming the specific gravity 

 of the film, enabled the bubbles to float in the atmosphere so as to 



