BLINDS BLOCKS. 



56" 



llauy, but was never in a very prosperous state, 

 st'ems to have declined greatly, after its founder's 

 return to France, in 1816. 



Institutions for the blind are confined almost en- 

 tirely to Europe, and they appear to be peculiar to 

 Germany, Switzerland, Holland, Denmark, France, 

 Britain, and Russia. Father Charlevoix, indeed, 

 says, that, in Japan, the records of the empire are 

 committed to the memory of the blind ; and Gallow- 

 nin estimates their number in the gigantic city ot" 

 Jeddo, alone, at 56,000 ; but neither of them men- 

 tions that there is any institution established for them. 

 The director of the institution in Vienna, F. W. 

 Klein, has published a good Lehrbuch sum Unter- 

 richte der Blinden, &c. urn sie zu burgerlicher 

 Brauchbarkeit zu bilden (Elementary Work for the 

 Instruction of the Blind, c., to render them useful 

 Citizens). The first, and, as yet, the only institution 

 of the kind in America, was commenced in Boston, 

 in the year 1829. 



BLINDS, in operations against fortresses ; the name 

 of all preparations which tend to intercept the view 

 of the enemy. There are several species: 1. A 

 fascine placed across the embrassures, to prevent the 

 enemy from observing what passes near the cannon. 

 2. Blinds before port-holes are shutters made of 

 strong planks, which are placed before the port-holes, 

 as soon as the guns are discharged, to obstruct the 

 enemy's view. 3. Single and double blinds. The 

 former consists of three strong, perpendicular posts, 

 five feet in height, between which are planks covered 

 witli iron plates on the outside, and thus made shot- 

 proof. This screen is furnished with rollers, to en- 

 able the labourers in the trenches to push it before 

 them, the latter consists of large wooden chests, on 

 four block wheels, which are filled with earth, or 

 bags of sand, and serve likewise in the trenches, 

 &c., to cover the soldiers from the fire of the 

 enemy. 4. Another kind of blinds used to pro- 

 tect the workmen in the trenches, are the chan- 

 deliers. Two square beams of timber are placed 

 parallel, and at a distance of six feet, on the ground, 

 and fastened by two cross beams. Upon the ends, 

 perpendicular posts are erected, and the interval is 

 filled up with fascines, at least to a height of five feet. 

 5. Blind is also the name given to coverings placed 

 over the most exposed parts in the saps or the for- 

 tress. These are made of beams, over which hurdles 

 or fascines are spread, that finally receive a sufficient- 

 ly thick layer of earth as a covering. 



BUSTER ; a topical application, which, when ap- 

 plied to the skin, raises the cuticle in the form of a 

 vesicle, filled with serous fluid. The powder of the 

 cantharis, or Spanish fly, operates with most certainty 

 and expedition, and is now invariably used for this 

 purpose. Morbid action may often be removed from 

 the system by inducing an action of a different kind 

 in the same or a neighbouring part ; hence the utility 

 of blisters in local inflammation and spasmodic action. 

 Exciting one pain often relieves another ; hence the 

 use of blisters in tooth-ache, and some other painful 

 affections. Lastly, blisters communicate a stimulus 

 to the whole system, and raise the vigour of the cir- 

 culation ; hence, in part, their utility in fevers of the 

 typhoid kind, though, in such cases, they are use<i 

 wiih still more advantage to obviate or remove local 

 inflammation. 



BLOCK, Marcus Eliezer ; a naturalist of Jewish de- 

 scent, born at Anspach, in 1723, of poor parents. In 

 the nineteenth year of his age, he understood neither 

 German nor Latin, nor had he, with the exception o; 

 some rabbinical writings, read any thing. Neverthe- 

 less, he became tutor in the house of a Jewish surgeor 

 in Hamburg. Here he learned German and Latin 

 and, besides, acquired some knowledge of anatomy 



4 is principal work is the Naturgeschichte der Fine fie 

 Natural History of Fishes), fol. 1785-1799, which is 

 idorned with many coloured plates. He enjoyed a 

 well deserved reputation, and died in 1799. 



BLOCKADE is the interception by one belligerent of 

 communication with a place occupied by another 

 Sational sovereignty confers the right of declaring 

 war, and the right which nations at war have of de- 

 stroying or capturing each other's subjects or goods, 

 imposes on neutral nations the obligation not to inter- 

 fere with the exercise of this right within the rules 

 and limits prescribed by the law of nations. In 

 order to render the communication with a place un- 

 lawful to a neutral, a blockading or besieging force 

 must be actually present, investing it, and sufficiently 

 powerful to render a communication with it danger- 

 ous to a neutral, and expose him to seizure by the 

 blockading or besieging force. A declaration ot 

 siege or blockade is an act of sovereignty, but does 

 not require, in all cases, a direct declaration by the 

 sovereign authority of the besieging belligerent ; for 

 its officers may be invested, either expressly, or by 

 implication, with authority to institute such siege or 

 blockade. It must, however, in order to be lawful 

 and obligatory on neutrals, be declared or sanctioned, 

 either expressly or by implication, by the sove- 

 reign power. It must also be delared or made pub- 

 lic, so that neutrals may have notice of it. If a 

 blockade is instituted by a sufficient authority, and 

 maintained by a sufficient force, a neutral is so far 

 affected by it, that, if he attempts to trade with the 

 place invested, either by carrying goods to it, or 

 bringing them away, the property so attempted to be 

 carried to, or from the place, is liable to be seized by 

 the investing party, and, in case of being siezed, ia 

 forfeited. 



BLOCKHOUSE, in fortification ; a house made of beams, 

 joined together crosswise, and often doubled, with a co- 

 vering and loop-holes, large enough for from twenty- 

 five to a hundred men. In addition to this, it is com- 

 monly covered with earth, to render it entirely bomb 

 and fire proof. It is usually sunk several feet into the 

 ground. Some forts of this kind contain two stories ; 

 and they are often fitted up to receive cannon. 

 Blockhouses are generally built in the form of a 

 square or a cross. Their use is to afford a feeble 

 garrison of an important place, which is very much 

 exposed, an opportunity of holding out against the 

 cannonade and assault of the enemy till they are re- 

 lieved. They also serve for bomb-proof guard- 

 houses, and places of last resort, in the interior of 

 intrenchments, and in the covered passages of for- 

 tresses, where the cannon are stationed. 



BLOCKS are pieces of wood in which sheaves or 

 pulleys are placed, for the purpose of forming tackle, 

 purchases, &c., in various operations in naval tactics 

 and architectural constructions. The mechanical 

 power is described in the article Pulley (q. v.) Blocks 

 are single, double, treble, or fourfold, according as 

 the number of sheaves is one, two, three, or tour. 

 The sheaves are grooved to receive the rope, 

 and have in their centre a brass bush, or triangular 

 piece of brass, to receive the pin on which they re- 

 volve. The sides of the block are called cheeks. A 

 running block is attached to the object to be moved ; 

 a standing block is fixed to some permanent support. 

 Blocks also receive different denominations from their 

 shape, purpose, and mode of application, which can- 

 not well be explained without the use of figures. No 

 less than two hundred different sorts and sizes are 

 made at Portsmouth, England, for the royal navy, 

 besides which there are various sorts used only in the 

 merchant ships. The machinery for supplying the 

 royal navy with blocks is the invention or Mr 

 Brunei!, an American. It enables four men, in a 



