408 



Mr. C. Brooke on the Nature 



[March 21, 



was shorter by one-half than the brown, was that the former represented 

 the slower growth by night, and the latter the quicker growth by day — the 

 white and the brown together representing an entire day of twenty-four 

 hours. But other observations by myself have given, as the average 

 growth of the hair of tlie head in persons who had been shaved, \ of an 

 inch for the week, and consequently of an inch for the twenty-four 

 hours. Now the length of hair comprehended by the white and the 

 brown in the present case is an inch, and consequently a much 



more active growth than is normally met with — corresponding, in fact, in 

 a similar ratio, with thirty- seven hours instead of twenty-four. 



I therefore refrain from speculating upon the cause of alternation of the 

 healthy and morbid structure presented by this case, and restrict myself to 

 the narration of the fact that during a certain space of time, amounting 

 to a day or more, the hair is produced of normal structure, while during 

 another space of time of undetermined extent the hair is produced un- 

 healthily, — that the periods of healthy formation correspond pretty accu- 

 rately in extent, as do those of unhealthy formation, while the latter, in 

 measurement, are only half as extensive as the former, — moreover, that the 

 differences of the pathological operation are, the production of a horny 

 plasma in the normal process, and of serous and watery cell-contents in 

 the abnormal process. 



I may further observe that it is by no means improbable that the 

 **dead" and faded hair which is met with after some illnesses and in 

 instances of debilitated health may be due to a similar pathological process, 

 although wanting in the periodicity and alternation which render the 

 present case so remarkable. 



III. " Remarks on the Nature of Electric Energy, and on the 

 Means by which it is transmitted.^^ By Charles Brooke, 

 M.A., F.R.S., P.M.S., &c. Received March 19, 1867. 



The writer has clearly shown the interchange of thermic and dynamic 

 energy at the point of junction of the bars of a thermo-electric element of 

 antimony and bismuth*, and he has also pointed outf that the dynamic 

 nature of electric energy is not less clearly indicated by the long-known 

 fact that an ordinary voltaic current always commences with a rush, as it 

 were, the instant that the circuit is closed. The dynamic cause of this 

 is clearly pointed out by an experiment due to the genius of Prof. 

 Wheatstone. If a tuning-fork, the tail of which is inserted longitudinally 

 into a wooden handle, like a file or chisel, be made to vibrate, and the end 

 of the handle rested obliquely on a table, the resonance of the table will 

 instantly be heard ; but on moving the diapason parallel to itself in any 



Phil. Mag. Nov. 1866. 



t Ibid. Dec. 1866. 



