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Physics, Astronomy & Cosmology / How does the length of a tunnel, at constant depth, vary with length?

« on: 24/12/2009 17:10:54 »

How does the length of a tunnel at a constant sea level directly relates to increasing atmospheric pressure in quantitative terms?

I understand that the atmospheric pressure increases with the length of the tunnel, but my google searches have failed to produce any data concerning any formula or model that could express in quantitative terms the effect of the length of a tunnel from a single entrance (such as a mine shaft or a tunnel digging operation in progress). Anyone know where I can find such data or can anyone have knowledge of a formula that I could use to gather data with?

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Famous Scientists, Doctors and Inventors / Historic Science: Nikola Tesla, How did he generate his alternating currents?

« on: 22/12/2009 05:51:10 »

I'm curious to hear what you all have to say. From another Tesla post it is easy to see that opinions on Nikola Tesla range in a great degree from being a quack to the most talented scientists ever. Whichever is true is none of my concern in this current pursuits of curiosity. I have studied some of the posthumously published papers of Tesla and apart from being difficult to grasp (mostly for late 19th century English and his own unique terms, ie "condensers" = capacitors,) it also is not written for the layman. His writing resemble more of a journal, which the papers are probably from and so assumes a high knowledge of his research subjects.

My question:

How did Nikola Tesla generate high frequency alternating currents?