The programme called for annual appropriations by each of the above-named powers of 100,000 francs (about $20,000 each), the appointment of commissioners and a general superintendent, the selection of a site for prosecuting the undertaking, and a board of scientific visitors, consisting of one member from each country.
It is unnecessary to detail the proceedings for the first few months after the organization of the commission. Prof. Watson, of Chicago, the author of a scientific treatise called "Prairie Geology," was selected by President Fillmore, as the first representative of the United States; Russia sent Olgokoff; France, Ango Jeuno; England, Sir Edward Sabine, the present President of the Royal Society; and Belgium, Dr. Secchi, since so famous for his spectroscopic observations on the fixed stars. These gentlemen, after organizing at Paris, spent almost an entire year in traveling before a site for the scene of operations was selected. Finally, on the 10th of April, 1849, the first ground was broken for actual work at Dudzeele, in the neighborhood of Bruges, in the Kingdom of Belgium.
The considerations which led to the choice of this locality were the following: First, it was the most central, regarding the capitals of the parties to the protocol; secondly, it was easy of access and connected by rail with Brussels, Paris and St. Petersburg, and by line of steamers with London, being situated within a short distance of the mouth of the Hond or west Scheldt; thirdly, and perhaps as the most important consideration of all, it was the seat of the deepest shaft in the world, namely, the old salt mine at Dudzeele, which had been worked from the time of the Romans down to the commencement of the present century, at which time it was abandoned, principally on account of the intense heat at the bottom of the excavation, and which could not be entirely overcome except by the most costly scientific appliances.
There was still another reason, which, in the estimation of at least one member of the commission, Prof. Watson, overrode them all—the exceptional increase of heat with depth, which was its main characteristic.
The scientific facts upon which this great work was projected, may be stated as follows: It is the opinion of the principal modern geologists, based primarily upon the hypothesis of Kant (that the solar universe was originally an immense mass of incandescent vapor gradually cooled and hardened after being thrown off from the grand central body—afterward elaborated by La Place into the present nebular hypothesis)—that "the globe was once in a state of igneous fusion, and that as its heated mass began to cool, an exterior crust was formed, first very thin, and afterward gradually increasing until it attained its present thickness, which has been variously estimated at from ten to two hundred miles. During the process of gradual refrigeration, some portions of the crust cooled more rapidly than others, and the pressure on the interior igneous mass being unequal, the heated matter or lava burst through the thinner parts, and caused high-peaked mountains; the same cause also producing all volcanic action." The arguments in favor of this doctrine are almost innumerable; these are among the most prominent:
First. The form of the earth is just that which an igneous liquid mass would assume if thrown into an orbit with an axial revolution similar to that of our earth. Not many years ago Professor Faraday, assisted by Wheatstone, devised a most ingenious apparatus by which, in the laboratory of the Royal Society, he actually was enabled, by injecting a flame into a vacuum, to exhibit visibly all the phenomena of the formation of the solar universe, as contended for by La Place and by Humboldt in his "Cosmos."
Secondly. It is perfectly well ascertained that heat increases with depth, in all subterranean excavations. This is the invariable rule in mining shafts, and preventive measures must always be devised and used, by means generally of air apparatus, to temper the heat as the depth is augmented, else deep mining would have to be abandoned. The rate of increase has been variously estimated by different scientists in widely distant portions of the globe. A few of them may be mentioned at this place, since it was upon a total miscalculation on this head that led to the present most deplorable results.
The editor of the Journal of Science, in April, 1832, calculated from results obtained in six of the deepest coal mines in Durham and Northumberland, the mean rate of increase at one degree of Fahrenheit for a descent of forty-four English feet.
In this instance it is noticeable that the bulb of the thermometer was introduced into cavities purposely cut into the solid rock, at depths varying from two hundred to nine hundred feet. The Dolcoath mine in Cornwall, as examined by Mr. Fox, at the depth of thirteen hundred and eighty feet, gave on average result of four degrees for every seventy-five feet.
Kupffer compared results obtained from the silver mines in Mexico, Peru and Freiburg, from the salt wells of Saxony, and from the copper mines in the Caucasus, together with an examination of the tin mines of Cornwall and the coal mines in the north of England, and found the average to be at least one degree of Fahrenheit for every thirty-seven English feet. Cordier, on the contrary, considers this amount somewhat overstated and reduces the general average to one degree Centigrade for every twenty-five metres, or about one degree of Fahrenheit for every forty-five feet English measure.