Volume 2
A selection of curious articles from the Gentleman's Magazine / [By John Walker].
- Date:
- 1811
Licence: Public Domain Mark
Credit: A selection of curious articles from the Gentleman's Magazine / [By John Walker]. Source: Wellcome Collection.
500/562 (page 482)
![But if’ ive farther add the great rivers, such as theDanube, the Don, the Dneiper, tlie Dnister, and several others, which fall into the Black sea, and flow through the Straits of Constantinople into the Mediterranean, as also that mul- titude of rivers, great and small, which run on all sides into tiie Mediterranean, it will be evident that the height which this sea receives annually by those means cannot be less than 30 feet. That evaporation should carry off all this water, seems impossible; for in that case it would be twenty-five times stronger than at Paris, which is not situated in a cold climate. A lake of between 40 and 50 feet in depth, without any issue, would not dry up probably in a year, even under the line. M. de Buffon has nevertheless asserted, that eva- poration is sufficient to carry off the surplus water which the Mediterranean receives annually. It was the authority of this celebrated naturalist that engaged M. Waiz to examine the subject with more exactness. For this end, he considers the manner in which salt is made in the Mediterranean by natural evaporation, by re- ceiving the water on a smooth surface to the height of an inch •and a half only. This water evaporates in 24 hours, in the hottest season in the year, provided no rain falls. Dr. Hoffman tells us, that a pound of the Mediterranean water contains two lots [a lot is the 32d part of a pound] of salt: but according to the Swedish Academician’s own experiments, Salt water doth not deposit its salt till the evaporation is Carried so far that there remain only five lots of salt to thir- teen lots of fresh water. According to this calculation, eva- poration on the coasts of the Mediterranean, in the hottest days, should carry off from each pound of water in the 24- hours, 24$ lots of water, which makes two thirds of an inch and a half which the water had in depth at the beginning. Jn deep cavities the evaporation must be more slow. In this planner the evaporation would in 24 hours, be one inch and a half. But if we grant that this inch and a half of water is entirely evaporated in 24 hours, the salt remaining quite dry, and making the 33d part of the whole mass; the daily- evaporation will then amount to 1 of an inch, and the an- nual evaporation to 44-^ feet, if it be equally hot all the year, and no rain falls. But as the hot weather lasts lor some months only, and there are few days without rain, and ^s there are even some whole seasons in which it rains constantly in the Mediterranean, and the evaporation is less, we cannot make the evaporation amount annually to 44 feet, especially as Fernery assures us, in his Course of Chyinistry,](https://iiif.wellcomecollection.org/image/b29339315_0002_0500.jp2/full/800%2C/0/default.jpg)
