Page:The American Cyclopædia (1879) Volume V.djvu/731

 DEAD SEA DEAF AND DUMB 727 and Lieut. Dale, the second officer, before the party left the country, fell a victim to the fever at Beyrout, where Lieut. Lynch also and near- ly all his men were attacked by the same dis- ease. In March, 1848, the latter party, des- patched by the United States government, and well equipped, passed across, with their boats drawn on trucks by camels, from the bay of Acre, over the mountains of Lebanon, and launched them in the lake of .Gennesaret. Thence they descended the Jordan, entering the river on April 10, and passing out of its mouth into the Dead sea on the 19th of the same month. They spent 21 nights on the shores of the Dead sea, and after having thoroughly explored the region, they left it on May 10, sending their boats across the desert to Jerusalem. Contrary to the opin- ion generally entertained regarding the pesti- lential atmosphere of this neighborhood, they found numerous animals living upon the shores of the lake, as doves, hawks, partridges, and hares, and also ducks swimming upon its sur- face ; and a curious fact regarding the birds, in- sects, and other animals here met with, is that they are all of a stone color, described as "the same as the mountains and the shore." In the sample of water brought back by the party no vestige of animal life was detected ; but in Jameson's u Philosophical Journal " of Feb- ruary, 1850, it is stated that Ehrenberg found an abundance of infusoria of brackish- water species in samples of the water and sediment brought to him for examination. The want of vegetable matter for food must necessarily to a great extent exclude animal life. A few plants which furnish soda in their ashes are occasionally found on the shore, and at the foot of the cliffs is noticed a scanty vegetation of cane and of the tamarisk shrub, their foliage sometimes of a light green and sometimes of a yellow hue, stained by the exhalations of sul- phuretted hydrogen ; but the few bushes to be seen often present their branches leafless and incrusted with salt, and the trunks of dead trees scattered here and there add to the des- olation of the scene. De Saulcy came to the conclusion that the sites of Sodom and Gomor- rah are to be sought for on the W. shore, and that those cities were not submerged, as is generally supposed. He found extensive ruins on the K". side of the mountain of Usdum, and a mile and a half to the northwest other ruins, which last he believed to be those of Zoar. Various analyses have been made by eminent chemists of the water taken from the lake, the results of which differ, in consequence no doubt of the different seasons of the year and por- tions of the lake at which the samples were taken, and also of the different methods of con- ducting the analyses. The specific gravity, as stated by Lavoisier and Klaproth, is 1'24; by Marcet, 1-211 ; by Gmelin, 1-212 ; by Apjohn, 1-153; by Salisbury, 1-1877; and by Lynch, 1*13. The constituents are thus given by dif- ferent authorities : TABLE I. SUBSTANCES. Pogg. Ann. Booth and Muckle, depth 1,110 ft. Genth, 1858. Chloride of potassium . . . 44 sodium 44 calcium 1-398 6-578 2-894 0-659 7-855 3- 108 1-0087 7-5839 2-8988 44 magnesium. . Bromide of magnesium. . Sulphate of lime 10543 0-251 Q-08S 14-590 Brunt, pctau'm 0-137 0-070 10-1636 0-5341 0-0901 Carbonate of lime Hydrated sesquioxide of iron 0-0042 0-0087 Silicic acid 0*003 0-0118 Nitrogenous organic mat- ter 0-0052 Solid parts in 100.... 21-7T3 26-419 22-3086 1 CABLE II. SUBSTANCES

Marcet. Klaproth. Muriate of lime 3-920 10-60 " magnesia 10-246 24-20 44 soda 10-860 7-80 Sulphate of lime. 0'054 Water. 24-580 75-420 42-60 57-40 100-000 100-00 The first of the above analyses, from Poggen- dorff's Annalen, is of a sample of the water procured from the north end of the sea, near the mouth of the Jordan. DEAF AND DUMB, The, persons who have not the sense of hearing, and in consequence want the faculty of speech. The primary defect is deafness ; dumbness follows from the resulting inability to control the vocal organs. Dumb- ness without deafness is very rare, and when not due to malformation is almost invariably a sign of idiocy. A person may be born deaf, or may lose his hearing by disease or accident ; deafness is thus medically classed as congenital or adventitious. For educational purposes a different distinction is made. Those who be- come deaf at so early an age that they have not learned articulate language, or speedily lose all impress of it upon the mind, share the mental characteristics of the congenitally deaf, and are classed with them as true deaf mutes. Those who retain some knowledge of articulate lan- guage, acquired through the ear, are called semi-mutes. The distinction lies not in the power or practice of speech, but in the habit of thinking in words. Deafness is more preva- lent than is generally supposed. By the deaf and dumb are usually understood only those so deaf that the ordinary means of vocal com- munication are unavailable with them. The number of these in a country has invariably proved to have been greatly under-estimated prior to careful enumerations; probably be- cause deafness, unlike blindness, has no out- ward indication to attract notice. But affec- tions of the ear producing a lower degree of deafness have received comparatively little at- tention; their extent is not appreciated even