12$ Mr, Tomlinsoris Experimeyits and [Aug. 



and shutting, and the estimable industry of the housemaid's 

 love of cleanliness ; all which operations would certainly 

 throw the glass into a vibratory state, so active, as to induce 

 fracture were it not that the vibrations are neutralized by 

 the wooden frame, and to this latter circumstance does the 

 glass owe its security and we our comfort ; for how incon- 

 venient would it be if so beautifully available and yet so 

 fragile an article as glass were to be subject to all the 

 casualties resulting from brittleness and imperfect elasti- 

 city! wind, rain, hail, would then compel us to substitute 

 the opaque and inconvenient defences of our ancestors, 

 wooden-shutters. I have been tempted into this common- 

 place digression from the circumstance of having just 

 knocked from my table on to the floor a valuable astrono- 

 mical diagram, painted on glass, and bordered with a thin 

 mahogany frame, sufficient, in this instance, it seems, to 

 prevent fracture. I now proceed to consider the secondary 

 tones produced by the vibration of metallic bells. 



68. I was anxious to ascertain what relation the secondary 

 tones of a large bell bore to its fundamental note, and for 

 this purpose I availed myself of the excellent musical ear 

 of my friend, Mr. Dodd, during his too short sojourn with 

 me, and we went accompanied by a flute to the large bell 

 of Salisbury Cathedral. We arrived at the belfry a few 

 minutes before six o'clock, when I immediately placed my- 

 self within the bell, and found that I could stand erect in it 

 without much inconvenience. A few seconds before striking 

 I closed my right ear with my right hand, and placed the 

 points of the fingers of my left hand in contact with the 

 interior surface of the bell : with the first stroke of the 

 clapper the effect was somewhat startling and unpleasant, 

 my left hand and arm became slightly convulsed, and the 

 sensation was that of handling the poles of a large galvanic 

 battery ; at the same moment I also experienced a sense of 

 fulness in the head, and a strong pressure on the tympanum.^ 



* These sensations may explain somewhat the evidently anxious and uncom- 

 fortable appearance of some domestic animals, such as cats, dogs, &c., during the 

 sound of certain notes on musical instruments. I have known pets of this descrip- 

 tion hurry from the room when music has commenced, and if the door were closed, 

 I have seen them stand whining for some one to offer them an exit. I am ac- 

 quainted with one sagacious dog that seldom barks in the drawing-room wherein 

 an upright piano stands, his bark causing several chords to vibrate sympathetically 

 to his evident annoyance. 



