Sunday, September 6, 2009

The Power of Heat and Iron

"Experiment (remarks Baron Liebig) has shown that a quantity of heat, sufficient to raise a pound of water one degree of temperature, will, when communicated to a bar of iron, enable it to elevate a weight of 1,350 lbs. to the height of one foot.

An interesting application of this fact was long ago made in the Conservatoire des Arts et Metiers, in Paris. In this building, which was formerly a convent, the nave of the church was converted into a museum for industrial products, machines, and implements.

In it's arch, traversing its length, appeared a crack, which gradually increased to the width of several inches, and permitted the passage of rain or snow. The opening could easily have been closed by stone and lime, but the yielding of the side walls would not have been prevented by these means.

The whole building was on the point of being pulled down, when a natural philospher proposed the following plan, by which the object was accomplished;

A number of strong iron rods were firmly fixed at one end to a side wall of the nave, and after passing through the opposite wall, were provided on the outside with large nuts, which were screwed up tightly to the wall.

By applying burning straw to the rods they expanded in length. The nuts by this extension being now removed several inches from the wall, were again screwed tight to it.

The rods on cooling contracted with enormous force, and made the side walls approach each other. By repeating the operation the crack entirely disappeared. This building, with its retaining rods, is still in existence."

1 comment:

  1. elevate a weight of 1,350 lbs. to the height of one foot
    Would anyone care to explain how this is done and at what cost. It appears to represent a significant mechanism of reclaiming energy from waist heat and if the above figures are proven to be correct, I must ask why they have been ignored for so long etc. The questions are obvious and the potential applications for energy production immense.