lii GENERAL SUMMARY OF SCIENTIFIC AND 



moistened with various liquids. His results show (1) that the 

 changes in tone produced by the absorption of liquids are also ac- 

 companied by a variation actually a decrease in the coefficient 

 of elasticity ; this effect is most marked with water, less with alco- 

 hol, and still less with oil ; and (2) the variations of tone of the 

 various rods w^hen wet, in comparison with a dry rod, follow a 

 definite law, a comparison of the condition of such a rod when 

 it has taken up a liquid showing a change in its modulus which 

 is quite definite in amount, and depends only on the liquid em- 

 ployed. 



Bosanquet has communicated to the Musical Association a second 

 paper on temperament, or the jiroper division of the octave, in which 

 he considers carefully all that has been done in the subject, and sug- 

 gests a plan of his own for the purpose. To test the question, he 

 has had a harmonium constructed with a compass of only four and 

 a half octaves ; but as each octave has fifty-three keys (!), the num- 

 ber of notes is quite suflScient. A previous instrument had eighty- 

 four keys in each octave. 



Professor Foster has exhibited to the Physical Society of London 

 the apparatus devised by Mach for sound reflection. It consists of 

 a mathematically exact elliptic tray, highly polished, and provided 

 with a tightly fitting glass cover. The tray is covered with precip- 

 itated silica well dried. Upon repeatedly discharging a Leyden-jar 

 between two small knobs placed in one of the foci, the finely di- 

 vided silica is seen to arrange itself in curves around the other 



focus. 



HEAT. 



Wallace has made a series of experiments on the Bunsen burner, 

 with a view to utilize it for general heating purposes. In one form 

 of burner devised by him the tube contains a simple strip of metal 

 so folded as to split up the rising currents, and so producing an inti- 

 mate mixture of the gas and air. Such a burner will not strike down. 

 In another form, called by him the tangent burner, the gas enters a 

 circular chamber tangentially, drawing in the air with it. In this 

 way the two are thoroughly mixed ; and if now they pass into the 

 tube of the burner through a piece of gauze at its base, the burner is 

 safe and trustworthy under all variations of j^ressure and quality of 

 gas. To utilize the burner for heating purposes, the author pro- 

 posed a stove six feet high and fifteen inches in diameter, with a 

 partition dividing it vertically from the bottom to within six inches 

 of the top. The burner is at the bottom of one division, and the 

 outlet pipe at the bottom of the other. 



Puluj has described a simple and easily constructed forni of ap- 

 paratus for determining as a lecture experiment the mechanical 

 equivalent of heat. It consists of two truncated cones of cast iron, 

 one of which is fixed, the other movable, revolving within the first 



