170 Mr. Tliomson's Note on the Form of the Fibres of Cotton, 



A represents tlie commencement of the collecting wire coils 

 in connexion with the rotating pointed piece B, dipping into 

 and leaving the mercury C simultaneously with the movement 

 of the collecting coils on the rotating armature of the magnet. 

 A' represents the terminations of the collecting coils in con- 

 nexion with the rotating disk B', which is always in the mer- 

 cury C ; D, a copper wire in contact with the mercury C, the 

 point of which is in contact with the wire that carries the 

 pointed piece B. The director wires, E E', are represented as 

 in connexion with each portion of mercury, and of course in 

 connexion with the collecting wire coils. On holding the 

 directors E E' in the wetted hands, a slight continuous thrill- 

 ing sensation is felt ; but if they are brought into contact and 

 then separated, on the moment of their separation a powerful 

 instantaneous shock is felt passing through the arms. The 

 same effect is produced if you remove the pointed piece B. 

 A continued scintillation and combustion of steel wire and sur- 

 faces, or of other metals, can be produced by substituting 

 them for the directors E E'. 



39, Charles Street, Parliament Street, Edward M. ClarkE. 



January 13, 1835. 



XXVIII. Note relative to the Form of the Fibres of Cotton, 

 By James Thomson, Esq., F.R.S, 



IN the first volume of the Bulletin de la Societe Industrielle 

 de Mulhausen, is a memoir by M. Josue Heilman, entitled 

 " Observations microscopiques sur la forme, la finesse, et la 

 force des filamens de Coton," in which he ascribes to the 

 fibres of cotton the precisely same form as that given to them 

 in the drawing of Mr. Bauer, dated February 11, 1822, which 

 accompanies my paper on Mummy Cloth, Lond. & Edin. Phil. 

 Mag. vol. v. p. 335. 



Mr. Heilman's " Observations" are accompanied by a 

 drawing by Mr. Edward Koechlin, of these fibres. Whoever 

 will take the trouble to compare the two drawings will detect 

 internal evidence of the one being derived from the other. 

 Mr. Heilman's paper being published in 1828, and mine in 

 1834?, renders some explanation necessary. 



In 1822 or 1823, Mr. Edward Koechlin was in England, 

 and during a visit he made to Primrose, he saw Mr. Bauer's 

 drawing, and requested permission to copy it, which was 

 granted. It is from this drawing and Mr. Koechlin's com- 

 munication that Mr. Heilman's " Observations microsco- 

 piques " are derived. The paltry fraud of appropriating to 



♦ Communicated by the Author. 



