Soundings made in the Mediterranean suffice to indicate depths equal to the average height of the mountains girding round this great basin; and, if one particular experiment may be credited, reaching even to 15,000 feet--an equivalent to the elevation of the highest Alps. This sounding was made about ninety miles east of Malta. Between Cyprus and Egypt, 6000 feet of line had been let down without reaching the bottom. Other deep soundings have been made in other places with similar results. In the lines of sea between Egypt and the Archipelago, it is stated that one sounding made by the _Tartarus_ between Alexandria and Rhodes reached bottom at the depth of 9900 feet; another, between Alexandria and Candia, gave a depth of 300 feet beyond this. These single soundings, indeed, whether of ocean or sea, are always open to the certainty that greater as well as lesser depths must exist, to which no line has ever been sunk; a case coming under that general law of probabilities so largely applicable in every part of physics. In the Mediterranean especially, which has so many aspects of a sunken basin, there may be abysses of depth here and there which no plummet is ever destined to reach.--_Edinburgh Review._ COLOUR OF THE RED SEA. M. Ehrenberg, while navigating the Red Sea, observed that the red colour of its waters was owing to enormous quantities of a new animal, which has received the name of _oscillatoria rubescens_, and which seems to be the same with what Haller has described as a _purple conferva_ swimming in water; yet Dr. Bonar, in his work entitled _The Desert of Sinai_, records: Blue I have called the sea; yet not strictly so, save in the far distance. It is neither a _red_ nor a _blue_ sea, but emphatically green,--yes, green, of the most brilliant kind I ever saw. This is produced by the immense tracts of shallow water, with yellow sand beneath, which always gives this green to the sea, even in the absence of verdure on the shore or sea-weeds beneath. The _blue_ of the sky and the _yellow_ of the sands meeting and intermingling in the water, form the _green_ of the sea; the water being the medium in which the mixing or fusing of the colours takes place. WHAT IS SEA-MILK?