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68 Thursday Oct 12th 1843 [[vertical squiggly line]] The weather is unfavourable for experiments with the electrical machine, and I have therefore directed sam to put in operation four of the cups of the Daniell's battery. Attempted to get a current between two coils with the ends open, but did not succed. [[text in remainder of page enclosed in a box]] Made some rough experiments on the heat produced in a conducting wire by the transmission of an electrical current, the result however was not very satisfactory, the time required for the long bell wire to arrive at its maximum temperature was much greater than I had supposed. I devised the following apparatus for the purpose of detering the heat, namely: [[image of apparatus as described in the text below]] A copper wire is passed backward and forward over the face of a [[underlined]] pile [[/underlined]] with a single row of elements, and over this is placed a plate of polished or gilded metal to reflect all extraneous heat. This apparatus is introduced into the circuit at different points, and the effect noted. On this subject, see Pelteas exp Annals de Chem vol- [[end page]] [[start page]] [[underline]]Saturday[[/underline]] Oct 14th 1843 69 Made an experiment to get electricity by a change of the molecular arrangement of a metallic wire. For this purposed, I introduced into the circuit with a copper wire and the French galvanometer a [[underlined]] thermo pair [[/underlined]], so that the electricity might pass with more difficulty in one direction than the other, and thus a current be exhibited. But when the wire was stretched, no effect was observed, although the wire became quite hot. Why should the stretching of a wire thus increase the temperature? The fact is in opposition to the general law that heat is absorbed when the density of a body is lessened. The wire when stretched occupies more space than before. (See Philosophia Magaze for year 1845) [[vertical note in left margin]] molecular action [[/note in left margin]] Tried an experiment on the heat produced by stretching a piece of indian rubber. When the rubber was stretched, it produced a great increase of temperature, and when it was worked backward and forward, there was a permanent increase of the heat. When a piece was broken, and the fresh formed surface applied to the thermo-pile, an increase of heat was indicated. (give this under the head of cappillarity) Monday Oct 16th 1843 I have thought of a plan by which the velocity of the galvanic current can be measured. For this purpose the wire should be wound [[strikeout]] around [[/strikeout]] at intervals around a bundle of fine wire, and over this a long wire, to produce a secondary spark at the moment of breaking the primary current, the sparks might be inspected by means of the revolving mirror, or by means of the revolving cylinder according to the plan I have proprosed in my new method of determining the velocity of a projectile. The plan of making a hole with the spark:
