In the course of a few hours the water rose to the surface and discharged itself at the rate of 600,000 gallons per hour. The depth attained was six hundred and two yards. The pipe by which the water reaches the surface has recently been carried to a height, nearly on a level with the source of supply. At present the water flows into a circular iron reservoir at the top of the scaffold, and it is thence conveyed by another pipe to the ground. The water is of good quality, and well adapted for culinary and domestic purposes. There is no fear of the supply proving deficient, as it is derived from the infiltration of a surface of country nearly two hundred miles in diameter. The Artesian wells of Elbeuf, Tours, and Rouen, which were formed many years ago, flow in an invariable volume. The ancient Artesian well at Lillers, in the Pas de Calais, has for above seven centuries furnished a constant and equable supply. When the source of supply is less extensive, these wells may be subject to variations, but the probability of this may generally be foreseen by the geologist and the engineer.

" The opportunity of ascertaining the temperature of the earth at great depths was not neglected during the progress of the works at Grenelle. Thermometers placed at a depth of thirty yards in the wells of the Paris Observatory invariably stand at 53 Fahrenheit. In the well at Grenelle the thermometer was 74 at a depth of four hundred and forty-two yards, and at five hundred and fifty yards it stood at 79. The depth attained