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readings were noted whenever a measurement of banding was taken. From the comparison of the relative humidity, temperature, pressure of the vapor in the atmosphere, and grains of water per cubic foot of air, it was observed that the changes varied with the differences of the relative humidity, and also increased with the continual tension of the weights.

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Referring you to the diagram showing the changes in the length of the bands, we took the weather as it came," until the twenty-third of January, when we endeavored to reproduce the conditions of a dog-day, by admitting steam into the room, until the desired humidity and temperature were obtained. Although the temperature was not in excess of that frequently reached, yet the effect of the moisture made the room seem much warmer; and swarms of insect-life threw off their winter torpor, and issued from the cracks in the floors. This moist. atmosphere caused all the bands, except the one with the linen core, to stretch. On the twenty-sixth of March the same experiment was repeated, with similar results. With slight increase of humidity, the bands contracted very slightly; and, with large increase of humidity, the same bands stretched.

Moisture, causing cotton fibres to expand laterally, shortens the length of the fibre by increasing its twist; if by excessive moisture the twist is increased largely, the fibres would be freed from the interlocking of the convolutions to such an extent, that, if there was a tension upon the whole cord, it would be lengthened by the slipping of the fibres upon each other. On the other hand, if the band had been stretched to the limit of elasticity, the fibres would be drawn in such close union that they could not separate easily, and only the contracting effects. of moisture would be shown, without being followed by excessive stretching.

With different textiles, these changes would cause variation to the extent that the adhesion of the fibres to each is changed by alterations in their diameter.

Mr. Edward Atkinson suggested that an absolute band might be obtained by combining different fibres in a proper manner. It was considered essential that the outside of the band should be of cotton, as this seems to be the only substance used for textile bands, which does not polish long before worn out. Two bands of this description were made, with cotton braided outside, one of them with linen, and the other with worsted,

core. This method of combining the two fibres I believe to be original with Mr. Atkinson. Cotton and linen have been twisted together by others; but such combination does not wholly accomplish the object, as the linen seems to lack sufficient resilience to check the stretch of the cotton, when the linen threads are twisted among the cotton. I have been informed that cotton and linen bands have been successfully used for wet-twisting by Mr. T. Merrick of Holyoke. Mr. Edward Kilburn writes that worsted bands were once used for cottonspinning at Lonsdale, and resulted in a saving of one-sixth of the power, until the expiration of about two months, when they became so polished by wear that it was necessary to take them off.

In three months and a half the linen-core banding stretched one per cent, and cotton banding five per cent. The daily results given are the average of a number of readings.

Your attention is called to the fact, that, while the band with worsted core changes in coincidence with the variations of the relative humidity of the atmosphere, the band with linen core changes in an inverse manner. “

With this, I submit the chart, and the results of the obser vations upon which they are based.

(See pages 73-74 post.)

Mr. BIRKENHEAD. Have you discovered any difference in the rate of motion of a pulley driven by an elastic band?

Mr. WOODBURY. No, sir.

Previous to the

Mr. BIRKENHEAD. I ask for this reason. war I was employed as a machinist in a mill; and, my attention being at one time called to two spinning-frames which were running at different rates of speed, I was led to investigate the matter. The overseer, who was at the time competing with others in other mills, had noticed that there was a difference in the production of the two frames, and was naturally anxious to remedy the difficulty. If I recollect aright, there was a difference of from six to eight revolutions in the speed of the front rolls, which made a difference of over ten per cent in the production. I spent some time in endeavoring to ascertain the cause. I placed my hands on the pulleys to see if I could discern any difference in temperature, but all seemed perfectly cool, with no indication of slip or friction. I compared the twist gears and the cylinder gears, and found them all to agree.

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core. This method of combining the two fibres I believe to be original with Mr. Atkinson. Cotton and linen have been twisted together by others; but such combination does not wholly accomplish the object, as the linen seems to lack sufficient resilience to check the stretch of the cotton, when the linen threads are twisted among the cotton. I have been informed that cotton and linen bands have been successfully used for wet-twisting by Mr. T. Merrick of Holyoke. Mr. Edward Kilburn writes that worsted bands were once used for cottonspinning at Lonsdale, and resulted in a saving of one-sixth of the power, until the expiration of about two months, when they became so polished by wear that it was necessary to take them off.

In three months and a half the linen-core banding stretched one per cent, and cotton banding five per cent. The daily results given are the average of a number of readings.

Your attention is called to the fact, that, while the band with worsted core changes in coincidence with the variations of the relative humidity of the atmosphere, the band with linen core changes in an inverse manner. `

With this, I submit the chart, and the results of the observations upon which they are based.

(See pages 73-74 post.)

Mr. BIRKENHEAD. Have you discovered any difference in the rate of motion of a pulley driven by an elastic band?

Mr. WOODBURY. No, sir.

Previous to the

Mr. BIRKENHEAD. I ask for this reason. war I was employed as a machinist in a mill; and, my attention being at one time called to two spinning-frames which were running at different rates of speed, I was led to investigate the matter. The overseer, who was at the time competing with others in other mills, had noticed that there was a difference in the production of the two frames, and was naturally anxious to remedy the difficulty. If I recollect aright, there was a difference of from six to eight revolutions in the speed of the front rolls, which made a difference of over ten per cent in the production. I spent some time in endeavoring to ascertain the cause. I placed my hands on the pulleys to see if I could discern any difference in temperature, but all seemed perfectly cool, with no indication of slip or friction. I compared the twist gears and the cylinder gears, and found them all to agree. I

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