B L I 



528 



L I 



in the America* A**alt tf Education. Captain H.isil Hall. 

 MII , usit. d the Hartford Asvlum, also gives some nr 

 ing particulars rcs|>ecting Juli* Brace in l.ts Tun-eli in 

 Nortk 



ii! tlu> -t.ii:-tics of the blind we have no very accurate 

 information. Their proportion to the whole population 

 varies from local causes: in Kgypt 1 in 300 are supposed 

 to be blind: in Knglatid not more than 1 in louo, but 

 this (jives a large aggregate. As improvable beings they 

 call for educatio uring under a serious organic 



defect they demand our sympathy and benevolent i 

 is our duty In support institutions for their education, and 

 to encourage those inventions which have been found in 

 any way adequate to their wants. The important work of 

 James Gall on the On^in nml Progrett <;/ Liti-rnture/or 

 the Blind supplies a vast variety of useful information on 

 the subject. 



BLINDAGE (called also BLIND), is a military Imild- 

 iiiL'. consisting usually of stout timbers, to secure troops, 

 stores, or artili. 



In fortresses, when regular casemates have not been con- 

 structed for the protection of the ammunition and provisions, 

 or of the soldiers, while not employed in active di; 

 vered buildings of a temporary nature are formed foi 

 purposes at, or previously to, the commencement of a siege. 

 The simplest are such as are made against the side of 

 some strong wall within the place, or, which is preferable, 

 against the revetment of the counterscarp, in a dry ditch, on 

 any of the front-, not exposed to the fire of the enemy. 

 These inclined blindages consist, when timber is plentiful, 

 of thick beams placed close together, and leaning against 

 the wall so as to make with it an angle of -15 degrees, one 

 extremity of each resting on a sleeper laid in the ground : 

 in other cases the beams are placed at intervals from each 

 other; over them are laid horizontal joists close togc-thcr, 

 and the whole is covered to the required thickness with 

 fascines and sods when they can be procured ; the entrance 

 is at one extremity of the building. This kind of blind- 

 age is also constructed to cover a man while employed in 

 piercing the escarp wall of a rampart, in order to form a 

 breach in it by the explosion of a mine. 



A blindage is sometimes formed independently of any 

 wall, by planting the timbers in the ground in inclined po- 

 sitions so that their upper extremities meet together in a 

 ridge, by which means the building resembles the roof of a 

 house, and the whole is covered with fascines and sods. 

 But generally an area is inclosed by a wall made of strong 

 palisades planted vertically in the ground, the roof being 

 formed of timbers disposed horizontally and close together, 

 above which conies the bed of fascines and earth. For a 

 small magazine the inclosing wall may consist merely of 

 gabions filled with earth ; the area being covered as before. 

 A blindage is said to be bomb-proof, when, from the 

 thickness of its roof, it is capable of resisting the shock of 

 loaded shells; and splinter-proof when merely capable of 

 securing persons within it against the fragments resulting 

 from the explosion of such shells. 



The French give the name of blindage to any building 

 already existing in a fortress, when a shell-proof covering 

 has been made to it in place of its proper roof: this cover is 

 obtained by placing great girders over the interior, and over- 

 laying them with joists :uid rarlh. It is recommended that 

 the walls, when not sullicicnllv strong, should be cut down 

 to a convenient height, and covered as before. On the ex- 

 terior of the building leaning blindages may be formed as 

 abcivo described, and sometimes the whole of the exterior 

 walls is protected in the same manner except at the in- 

 tended entrances, which ore generally opposite to the piers 

 between the doors and windows, where some of the in- 

 clined timbers are omitted: but occasionally the walls and 

 re merely strengthened and supported by shoar.s or 

 inclined props firmly fixed below in the ground, and above 

 jainst the extremities of the girders. For these 

 kinds of blindages such buildings should be selected as have 

 their lengths in the prut) ihlc direction of the enemy's lire, 

 to moid t'ncir being too much exposed. 



To I the artillery on the ramparts of a 



lortress, shell-proof blindages arc formed, by planting in the 



ig puhsadcs vertically on each side of tli- 

 from the interior slope of th parapet to tli .<. ;I|H>UI 



eighteen feet from thence, nrross the tcrr^plcm or upper 

 -nrUce of the rampart: and R roof is made \v ith timlx-rs. 

 which also cover the embrasure as far as six feet from its 

 neck, or interior extremity. These blindage* are open to- 



wards the rear, and the guns fire through the embrasure* 

 as usual. It has also been recommeiu: 

 age in the thickness of the parapet itsch 



vered with timbers, fascines, and earth : the. 11 

 side should be open, but the exterior mav i i.\ a 



number of stint timbers placed horizontally, so as to : 

 a wall four feet (luck, through which the embrasure* may 

 be cui like tin' portholes of a ship. 



In the attack of fortresses, when the trenches of the be- 

 siegers become subject to a plunging lire Iroin the 

 t'uey .ire protected by blindages : these are funned by I 

 rectangular frames of timber vertically along the two side* 

 of the trench, and placing similar frames across the t 

 so as to rest on the upper extremities of the former ; the 

 roof frames carry a laver of fascim s, which is covered with 

 earth or raw hid. 



Blinded trenches of this kind were formerly much 

 by the ; i protect their descent into the ditches of 



I'm tilled towns; one of tins kind wii- executed by the French 

 for that purpose when they besieged Daiizig in 1813. 



BL1NDNKSS. jSee KYK.] 



BLIND-WORM (zoology), the English name for a 

 species of the third subgctius of the lumily of Aiifumltf, 

 les Orvetg of the French, and the genus Angui* <! I.in- 

 n;eu-. This family have; a bony head, their teeth and 

 tongue resemble those of the lizards distinguished by the 

 name of Seps, and they have three eyelids : they are, in 

 short, as Cuvicr observes, so to speak, Seps-lizards without 

 feet. [See SKPS.] 



[Head of Blind-worm.] 



Before we enter into a description of the reptile whose 

 name stands at the head of this article, it may not be unin- 

 teresting to trace the steps by which nature, leaving the 

 form of the lizards, arrives at that of the snakes. Proceed- 

 ing in the lizards from Srps to Bipet, from liijwx to Chttl- 

 cicles, and from Chalcides to Chirntes, forms almost insen- 

 sibly becoming more and more serpentine, she arrives at the 

 .liifftiiiitr or Snakes, which may be said to form the con- 

 neeiing link between the lizards and the true serpents. [See 

 SKRPKNTS.] These Anguidee are characterized externally 

 by imbricated scales which cover them entirely . Thei 

 according to Cuvier, tour suhgcm-ra : in the three first of 

 which are to be found, under the skin, the rndinie 

 some of the bones of the anterior extremities and of the 

 pelvis. In the last suhgenus there is no vestige uf such 

 bones, nor of a sternum (breast-bone). 



\\e will give a slight sketch of these subgenera. and so 

 endeavour to convey to the reader the place which the 

 blind-worm is supposed to occupy in this graduated 

 In the first of these subgenera, I'M m/ojius of Merreni (the. 

 ScheltopusiAs, see SCHKLTOPUSIK), the tympanum or drum 

 of the ear is visible externally : nn each side of the vent 

 there is a small prominence, which is the rudiment of :\ 

 femur (thigh-bone), and this bone is attached to a true pel- 

 vis hidden beneath the skin. The anterior extremities are 

 scarcely marked by an external fold hard to be seen, and 

 there is no humerus (arm-bone) within. One of the lungs 

 iourth part less than the other. 



The second subgenus, Ophitawntu (snake-lizard) of i 

 din, has many points of resemblance with the Scheliopu- 

 siks, but there is no appearance of posterior extremities or 

 limbs. The tympanum, however, is still visible, and tin- 

 leave a fold on each side of the trunk. The small 

 lung is about one-third of the size of the large one. 

 OPHISAURUS.] 



In the third subgenus (.Angui* of Cuvier), under which 

 the blind-worm is arranged, not only is there no appearance 

 of any limbs externally, but even the tympanum is hidden 

 under the skin : the maxillary teeth are compressed and 

 hooked, but there are no palate teeth. The body is enve- 

 loped in small imbricated s<-a].-. and there is no fold at tin? 

 side. One of the lungs is less than the other by one-half. 

 Such are the characters of the Orrcts properly so called. 



Thc.se tl. .era have still an imperfect pelris*, 



: tlli> imjinf. . : 



'rafila Im (xMtariorexInBitjr ud Dot a rudtMlary p. 



.1 huCiyplopoda,* 

 l.uicly u[ (>i>hHlj.ini having the rudiment! of a foot concealed uudci lti ikiu, 



