336 Intelligence and Miscellaneous Articles. 



ployed for the bending, a weight of 3 kilogrammes was suspended 

 beneath, and left to itself for 7 days (from the 11th to the 17th of 

 February). It was suspended in this way : at a distance of 3 cen- 

 tims. from each end an aperture was pierced with a hot wire ; and 

 through this a string was drawn. On the 16th, when the tempe- 

 rature rose, the resulting softness of the ice had this effect, that the 

 string gradually cut through it. Yet, between two marks quite 

 close to the ends, consisting of two pointed pieces of wood frozen 

 into the bar and with only the points protruding, up to that time 

 a lengthening of the cylinder 1 millim. appeared. By the string 

 cutting through, the marks also changed their position, so that the 

 further extension until the ice parted could not be with certainty 

 determined. 



It is therefore shown here also that a pull continued for a longer 

 time, even when it is slight, stretches ice, that near its melting- 

 point it shows itself like other bodies yielding to pressure as well as 

 to pull, and especially that, towards the former, at a temperature 

 in the vicinity of zero, it is to be regarded as an eminently 

 plastic substance. 



The phenomena of the motion of glaciers will after this appear 

 less surprising ; and in like manner the behaviour of ice at different 

 temperatures towards pressure throws a new light on the fact that 

 the velocity of glacier-motion rises with the temperature. Since the 

 glacier-ice and the air over it possess, at least in the summer months, 

 a temperature which departs very little from the freezing-point, a 

 very slight pressure suffices to set it in motion ; and I think that the 

 so-called sliding theory receives fresh support from the experiments 

 above described. — Poggendorff's Annalen, vol. civ. pp. 169-174. 



ON MUSICAL CONSONANCE. 



To William Francis, Esq., Ph.D. 



Bear Francis, 

 Would you kindly permit me, in your next Number, to express 

 my indebtedness to Mr. Sedley Taylor, Professor Mayer of Hoboken, 

 and Mr. Bosanquet for pointing out an error in the statement of 

 Helmholtz's theory of Consonance in my eighth Lecture upon Sound? 

 It would be easy, if it were of any use, to show the origin of 

 this mistake. Suffice it to say that it has been long known to me, 

 that it has been corrected in the last edition of my work on Sound, 

 and that the corrected statement of the theory, though necessarily 

 brief, is, I have reason to know, regarded by Helmholtz as "per- 

 fectly clear and exact." 



With regard to the experimental data referred to in my eighth 

 Lecture, I may have something to say on a future occasion. 

 I am, dear Francis, 



Faithfully yours, 



John Tyndall. 

 Royal Institution, 

 September 15, 1875. 



