220 Notices respecting New Books. 



node is near the free extremity of the bent wire ; as the wire is 

 raised and the angle increases, the node rises nearer to the bend. 

 It is also worth observing that, in any combination, the distance 

 of the node from the free extremity of the wire, compared with 

 its distance from the bend, is approximately the same as the 

 ratio of the interval depicted by the figure. 



I have now, in conclusion, to refer to another arrangement for 

 effecting the combination of rectangular vibrations, which though 

 rather less simple than the one just described, has the merit of 

 being more easily adjusted and more permanent in character. 

 This arrangement, shown in figure 2, has been adapted by Mr. 

 Ladd from an instrument devised by Professor Helmholtz. 



Two flat pieces of steel are here welded at right angles to each 

 other into a single rod. The upper part («) is tapering, and on 

 its summit is fixed a polished silver bead. The lower part (b) is 

 capable of being firmly fixed in a suitable support. According 

 to the height at which b is clamped, so a corresponding portion 

 is allowed to enter into vibration. A combination of the vibra- 

 tion of a with that of b can thus be obtained in any given ratio. 

 Complete command of any figure can be had by marking its 

 position on the lower strip of steel ; and so nice an adjustment is 

 possible, that an almost absolutely steady figure can be secured 

 with a little care. 



If I may presume to suggest a name, I propose to call the 

 instrument described in this paper a Tonophant. 



XXIX. Notices respecting Neiv Books. 



A Manual of Inorganic Chemistry, arranged to facilitate the Experi- 

 mental Demonstration of the Facts and Principles of the Science. 

 By Charles W. Eliot and Frank H. Storer. Second Edition. 

 London : Van Voorst. (Pp. 605 and lix.) 

 A T a time when the attempt has become general in this country 

 * *• to elevate natural science to the rank of a branch of education, 

 even the minutest incident of the transition may be considered im- 

 portant. If report be correct, we are about to be rescued from the 

 hands of the popular lecturer and placed under the regimen of the 

 schoolmaster ; and even those by whom the advantages and func- 

 tions of science are but little understood manifest an earnest interest 

 in every symptom of the change. 



The number of chemical manuals which have been published du- 

 ring the last three years, for the most part somewhat hastily, are a 

 sufficient proof that chemists expect a new epoch in national educa- 

 tion. We have now in common circulation thrice the average 

 amount, perhaps, of such works ; and new ones, as well as new 

 editions of old ones, are announced as preparing for the press. Most 

 of these books are literary experiments, and it is very unlikely that 

 more than one or two of them will achieve a lasting reputation. Not 



