PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 631 



rcod is dotci-niincd by this plaiiiiiy,-. So accurately does tliis planing- ma- 

 chine woi'U, that the reed, when delivered finished iVoin the machine, is 

 within a sixleenth of a true note, and requires only a little adjustment to 

 make it perfect. When we add that the tuner, in giving the reed its pro- 

 per pitch before it is finally placed in the instrument, uses a smooth file, 

 and that one rub of this file is suflicicnt to alter the tone materially, it will 

 be seen that the machine must be very nicely adjusted to make the reeds 

 correct, or nearly so, at first. 



THE REKD BOARD 



is simpl}' a strip of plank, the length of the key-board, full of little cells, 

 as shown in fig. 3, at A, etc. In the middle cell, as illustrated, will be 

 seen a rced-block and reed in its place in a cell. 



The cells, or tubes as the makers cull them, where the reeds set, are all 

 made by a most ingenious machine, contrived by Mr. Carhart. This ma- 

 chine is automatic, and the strip of plank out of which the board is made, 

 liaving been placed in a certain position, the cutter goes on and produces 

 all the cells, as at A, and performs its oflice with a regularity and exacti- 

 tude which is almost human. This machine will rank with the automa- 

 tic lathe of Blanchard; for it is not oidy capable of executing work in 

 straight lines, but also carves scrolls for lyres, and similar work with such 

 nicety and rapidity that no hand work can approach it. ' The cutters revolve 

 with great velocity, 7, TOO times a minute, and the speed of the driving 

 belt is just one mile in a minute. 



There is another little detail in this rood-board which commands our 

 attention, and this is the small groove the reed-block^sets in. This groove 

 is about a tenth of an inch wide and deep, and is made by a swiftly 

 revolving cutter. Each groove is an exact fac simile of the other, and 

 those made years ago will fit any reed-block made to-day. One of those 

 tube boards is cut in five minutes, and the rapidit}' with which the details 

 are executed is worth}' of notice. 



Beneath the tube-board is a series of valves, lined with soft kid-skin, which 

 close the cells. When either of these valves is raised by depressing a key- 

 on the finger board of the instrument, the air is admitted to cells in which 

 the air has been partially exhausted and in passing by the reed or tongue 

 gives it such vibration as to produce a sound. 



In the discussion which followed, many interesting statements were 

 made by Dr. Rowell and others. The most essential fact elicited was that 

 the reeds are now made of an alloy consisting of copper, 45, zinc, 45, and 

 nickel, 10, which is nearly unaffected by the moisture in the air. These 

 vibrating tongues are all made to a standard pitch so that if one ia 

 injured an order may be sent for another to go by mail, and it will be sure 

 to accord. 



After deciding to continue the discussion of musical instruments at the 

 next meeting, the Association adjourned. 



