Abstract I n August the author made an excursion into the wild and rocky valleys of Laridjan, on the northern side of the Elburz chain, to examine some mineral springs near the village of Aske. This village is placed on a steep declivity above the impetuous torrent of the Laur, and is about 40 or 45 miles E.N.E. from Tehran, and near where latitude 36° N. intersects longitude 52° E. It is only a few miles from the lofty and slumbering volcano Demavend†. Round Aske the country is chiefly limestone, with dark-coloured pudding-stone, and in several places large tracts of sandy grit, in many precipitous heights of which numerous caves and hermitages have been excavated in olden times. The most celebrated spring in the neighbourhood is the Ab-i-garm (hot-water),—a warm sulphur-spring that rises on one of the spurs of the Demavend, about six miles to the eastward of Aske, on the left bank of the Laur, and probably about 2000 feet above the bed of that river. The principal mineral ingredients of this spring are sulphur and naphtha, with some iron and lime. On the 15th of August, the temperature of the atmosphere in the shade, at two p.m. , being 75° F., the temperature of the spring at its source was 150° F. From hence it flows down the side of the mountain to a large basin about 15 feet long, 10 broad, and 4 deep, over and around which a large stone bath has been raised. The temperature in the basin is about 118° F. Here in summer thousands congregate from every part of Northern Persia. The bath seems to be beneficial in rheumatism, neuralgia, and some diseases of the skin. Formerly there issued from the rock, a few feet from the Ab-i-garm, a cold spring of pure water, which disappeared after an earth-quake about forty years ago. The tepid baths of Aske are about half a mile from the village on the right bank of the Laur, and about 250 or 300 feet above that river. These are used both for bathing and drinking. Lime and carbonic acid gas are abundant in this water. There are several springs of different dimensions, the bathing-basins of which are apart from each other at distances varying from ten to fifteen yards. At half-past five p.m. , the temperature of the air in the shade being 71°F., the water in the centre of the largest basin (where the bubbles are thrown up by the gas to an elevation of 6 or 8 inches above the surrounding surface) was at 82°— the average of the temperature of the other springs near by. On the left bank of the Laur a small bubbling spring of water, similar to those last mentioned, had a temperature of 85° F. These tepid mineral springs lying to the eastward of Aske, do not appear to be affected by the intervention of the deep and rocky bed of the Laur. To the westward of Aske, at the distance of about 1½ mile, on the left bank of the river, and not more than 150 feet above its bed, is a fine cold ehalybeate spring : besides iron, this probably contains carbonic acid gas and a small portion of sulphur. Its temperature was found to be 50° F., that of the atmosphere being 73° F. It is not disagreeable to the taste, and in some complaints is found very strengthening and efficacious. In conclusion, the author referred to the undeveloped riches of the Elburz—its coal, iron, copper, silver, sulphur, marble, and other mineral treasures.