350 E.vperimciiis on iJie Smul in Wheat. 



It should be observed, tliat all the above experiments were 

 made with the bars inclined in the direction of the dip|)ing 

 needle, or nearly in that direction, and it will be seen that the 

 negative attraction was the greatest where the natural attrac- 

 tion WPS the least; that is, opposite the luidtUe of the bar, or 

 in the })!ane of no attraction. I was led, therefore, to make 

 a few experiments with the bar inclined at right angles to its 

 former position, but the results Avere by no means so strongly 

 marked as in the preceding expei'inients : we always foimd n 

 certain quantity of negative attraction, but it was very incon- 

 siderable, never amounting to more than 2^°. 



I also made one experiment with an iron 211b. ball, but tlie 

 heat was too intense to make any very accurate observation. 

 The numbers obtained were 



Cold attraction +13° 30' A^'hite heat 0^ O'. 



Red heat —3° 30'. Blood-red heat + 19° 30'. 



It may be })roper also to state, that, being doubtful how far 

 the heat itself, independent of the iron, might be the cause of 

 the anomalous action above described, I procmed two coj^per 

 bolts of rather larger dimensions than my iron br.rs, and had 

 them heated to the greatest degree that metal would bear; 

 but on applying them to the compass, no motion whatever 

 could be discovered in the needle. 



The only })robable explanation which I can offer by way of 

 accounting for these anomalies, is, that the iron cooling faster 

 towards its extremities than towards its centre, a part of the 

 bar will become magnetic before the other part, and thereby 

 cause a diilerent species of attraction ; but I must acknow- 

 ledge, that this will not satisfactorily explain all the observed 

 pha?nomena. The results, however, are stated precisely as 

 they were noted dm'ing the experiments, and others inoie com- 

 })etent than myself will probably be able to deduce the theory 

 of them. 



LXIX. Exjicriiucnts nn the Smul in Hlieat, Bj/ Mr. Samv El. 

 Ta YLO R , of Bnngaij. 



To the Editors of the Philoiojihical Magazine andjotirnal. 



Genti.e.-mkx, — \Jv the uifectious nature of the disease called 

 smut in wheat, I liave long been convinced from a series of 

 ex})erinients and observations Avhich cannot have deceived me. 

 By snnit I wisii to be clearly understood to mean that kind 

 wliich shows itself in small roundish balls or bladders, nearly 

 similar ui .ippcarance, wlieii growing, to eajs of wluat: but 



which, 



