that which falls upon a surface which will be enclosed in a circle whose center was the mouth of the well, and whose radius was the depth of the well. This statement was made independent of any lay of the land or the geological formation, and without any consideration whatever of the surrounding country. Fortunately this can be met very easily. Thirty barrels of water were pumped from the well each day. We know the amount of rainfall in Michigan per year, and we can calculate very easily the number of barrels that would fall upon this surface enclosed in a circle whose center was the mouth of the well, and whose radius was the depth of the well; and as the result of such a calculation we find that the amount of rain falling upon this surface during the year would not supply the well more than two or three days. Returning home and detailing the trip to Dr. Langley, he suggested that a direct experiment might be made to see whether matter would pass from the proposed cemetery to the well or not. He tested the water of the well for lithium, a substance easily detected, found it was absent, then had a salt of lithium sown over the proposed cemetery, and then examined the water of the well each day thereafter; and on the eighteenth day after the lithium was sown over the cemetery it was found in the water of the well, showing that the water did unquestionably penetrate the soil, pass down to the impervious bed of clay which was the watershed upon which the water in the well collected, and thence into the well. Notwithstanding proofs so positive as this, a learned judge in Michigan dismissed the case, and allowed the cemetery to be located there, with a possibility of poisoning a number of families. As a result, the families of the neighborhood had to discontinue the use of their well-water.” Professor Vaughan holds that the popular belief that if water filters for any distance through the soil it is purified, is an erroneous belief, and cites a number of experiments made by himself, and numerous cases, in support of the assertion. According to Dr. H. B. Baker, secretary of the Michigan State Board of Health (_vide_ Report for 1874, p. 136), a terrible epidemic of cerebro-spinal meningitis, that wasted the village of Petersburg in the early part of 1874, was attributable to a spring five paces from a house and 15 paces from a cemetery, which is on ground from 12 to 15 feet higher than the level of the spring. About 18 paces from the spring was a recent grave. Prof. R. C. Kedzie, of the Michigan State Agricultural College, to whom some of the water was sent for analysis, concluded his report as follows:—