M. de Cossigny wrote, in 1750, about Chaux-les-Passavant. He made a plan of the cave and took many observations in April, August and October, and concluded that the interior condition of the cave does not change noticeably from winter to summer, no matter what the external conditions of temperature may be; that what people say of greater cold in summer, vanishes before actual experience and that, as a state of freezing reigns more or less continuously in the cave, it is not surprising if the ice accumulates. Apparently he was the first to notice and insist on the necessity of drainage to the cave through cracks in the rocks. He also made a series of observations disproving those of M. de Billerez, as to the presence of any kinds of salts in the rocks or ice. Hacquet, in 1778, thought that the ice in the cave at Lazhna-gora formed in winter, but he also thought that there must undoubtedly be some salt in the water. He says he found ice in the cave in the spring, and that his companion, a priest, had never found any in winter. He therefore concluded that by that time it had all melted. Romain Joly, in 1779, claims to have visited Chaux-les-Passavant on the 19th of September (year not given). His account seems largely borrowed from the one in the _Histoire de l'Académie Royale des Sciences_, in 1686. He says: "This ice is formed by the drops of water which fall from the roof, and which freeze because of the chill of the cave. In the winter there is no ice, but running water." He says nothing, however, about the ice forming in summer. The _Citoyen_ Girod-Chantrans visited Chaux-les-Passavant in August, 1783, and reached the conclusion, from all he saw and heard, that the cave did not freeze in summer nor thaw in winter, and that it was really a natural ice house. He was aided by the notes of a neighboring physician, Dr. Oudot, who had made observations in the cave, and among others, had placed stakes of wood, on the 8th of January, 1779, in the heads of the columns he had found in the cave; and on the 22d of February, 1780, had found these stakes completely covered with ice, forming columns 30 centimeters in diameter. Hablizl, in 1788, wrote that the ice in the cave near Karassoubazar formed in the spring by the snows which melt, run into the cave, and refreeze. He also thought that there was less ice there in the fall than in the spring, that it diminishes in July and August, and that the idea, current in the neighborhood, of the formation of ice in summer, is a mistake.