BLOOB 



BLOCK. 



often prow i 

 aBtinrpated from UM 



JHSlffTr.^-' 



" 



But hatever be their mod. o( operation, the fact is certain that 



" r 'wdM-* than oould have bean 

 on which they act, and from the 

 i. as already steted.they are 

 sated in a particular organ 

 by no means without advantage in 



la which lh.-sy-.rn k Uy and deepiv involved ; but U*n 

 can only W obtamed (rum them afterbleedin, purging. and 

 racuanU have Inimiit or subdusd UM general action of the 

 In this case they often complete and render permanent the 

 t derived trutu UM preceding remedMs. 



For UM reason already assigned, UMT are most commonly employed 

 lerfully on the general system) in pneumonia 

 i of the lung), in gastritis (inflammation of the stomach), 

 ia hepatitis QssMlimisll n of UM liver), in phrenitis (rnflimmation of 

 the brain), and ao un ; but there are diseasss of the nervous system in 

 which UMT are decidedly uaeful, as in spasmodic affections attended 

 with pain but without inflammation, in the paroxysms of angina 

 psctona and of spasmodic asthma, in epilepsy, catalepsy, hysteria, 

 nararnia, etc. 



- k sometimes derived from the application of blisters through 



> and direct action u stimulants, chiefly in full habits, 

 to which languor is the consequence of over-distension. In theae oasas 

 they excitethe whole system, and produoe an exhilarating effect. A 

 gaiillaniin once highly distinguished at the bar, and of brilliant con- 

 vivial powers, always applied a bliatcr when he wished to chine in 

 either sphere, and the effect waa produced u aoon u the warmth in 

 the part began. Many peraona, even though they feel acutely the paiii 

 produced by busters, declare that the relief from the prerioua languor 

 counterbalances all their suffering*. 



The application of a blister u aometimea successfully employed as a 

 of directly lessening pain. The excitement of one pain diminishes 

 hence the relief afforded in tooth-ache and other painful 

 Although in general bliaten relieve more pain than they give, 

 yt in some irritable skins aid in some irritable states of the system 



in constitutions thus predisposed to irritation from the 

 operation of this remedy, which constantly produces good or bad effects, 

 just aa its application ia well or ill timed. One painful affection occa- 

 sionally n3q""d (strangury) ia effectually relieved by on anodyne 

 injection thrown into the rectum, consulting of four or six ounces of 

 thin tepid gruel, with thirty or forty drops of laudanum. 



BLOCK (German, BUttt ; Dutch, lUottm ; Swedish, Slceppt-bloci- ; 

 French, Pomlie ; Italian, BouUi ; Spanish, tfot*a; Portuguese, 

 Mo*tAa ; Bam, Bloti), an instrument generally made of wood, but 

 anmcitimai of iron. It U much employed in the rigging of ahips to 

 give facility to the raising or lowering of the marts, yards, and sails, 

 and for such other purpose* aa require and admit of the application of 

 UM pulley a block, aa used on board of ahips, being simply a pnllej 

 in the greater part of ita modifications. One description of Mocks, to 

 which the name of dead-eyes has been given, is not a pulley, being 

 unprovided with sheaves. These dead-eyes are used for setting up and 

 fastisihsj UM shrouds and other standing rigging of the ship, while 

 ahsaTed block* are used for the running rigging. The more usual form 

 of blocks of both descriptions U that of an oval spheroid, flattened at 

 opposite aides. Dead-eyes are made out of one piece of wood, pierced 

 with UM requisite number of boles, through which the standing rigging 

 I. Single-sheaved blocks are made up of three distinct (arts, 

 UM shell, the sheave, and the pin which serves aa an axis 

 f which the sheave revolves. Some blocks are made with two, 

 and others with 'three, and even four sheaves, which all revolve on 

 IM gams pi** or axis, and consequently parallel to each other, in 

 separate chambers formed for that purpose in the shell of the 1-1.. 1. 

 Block* in all their varieties are used also for the purpose of raising 

 weights in every department of mivhanios and constructive ope- 



The construction of blocks would seem to be a very simple opera 

 tion, such as any man accustomed to work in wood could perform v. ith 

 facility and accuracy ; l-nt this in practice is not found to be the case, 

 as the parts must be fashioned and fitted together with the greatest 

 poasfbls accuracy, in order to insure their easy working when put 

 Ulgetlssf a circumstance of considerable importance in the manage- 

 ssnt of a ship. For this reason, block-making has long formed a 

 nbstaotiv. branch of manufacture, and is carried on either i.y itself, or 

 hi conjunction only with mast-nuking. 



,1 1801, Mr. Brunei succeeded In computing a perfect working 

 ostructing both the shells and aheaves of blocks. This 

 Ubebsf submitted to the Inspection of the Lords of the Admiralty, 

 UneuUun was at once adopted by government, and Mr. Brunei 

 was engaged to superintend UM construction of the requisite machinery 

 at Portsmouth, upon a scale sufficiently large for making blocks to 

 supply UM whole naval service of the country. The wnipl. 



fall operation until 

 use at Chatham 



. 



occupied nearly six years, and was not brought into 

 til Heptember, 1808; but similar machines are now in 

 and elsewbsrw. 



of machines devised by his inventive genius for the 



formation of the blocks employed in raising burdens, and particularly 

 in the important service of moving the rigging of ships, contains so 

 many ingenious processes for gaining the proposed ends with the 

 utmost accuracy, and, at the same time, with the least possible labour, 

 as to justify the opinion that.it constitutes one of the noblest triumph" 

 of mechanical skill; and, in this arti.-!.-. it i- intended to give a brief 

 description of the principal parts of which it is composed. 



The machines may be said to consist of many saws and lathes ; by 

 these the work is performed, from the operation of cutting up a log 

 of timber, to that of |>oli*hing the pins on which the pulleys turn ; and 

 motion ia communicated to all of them by a single steam-engine. 



A straight saw worked backwards and forwards, horisontally by the 

 engine, cute off in succession different portions transversely from the 

 log of timber (elm) which, for this purpose, is made to rest on a table 

 or low bench ; the portions cut off being of the prn|>er lengths for t ),.- 

 dimensions of the intended blocks. For the smaller logs a circular 

 saw is used ; it cute the tree transversely, and consequently ite plane ia 

 perpendicular to the axis of the Utter : the saw is capable of l>eing 

 raised vertically, or moved horizontally at pleasure, in order that it 

 may be made to enter the wood above or below, or on either aide. 



After the log has been cut in slices, the Utter are brought to what 

 U called the ripping saw: this is circular; and ite plane standing 

 /vertically, in part above the level of the table, it serves to cut the 

 slices into rectangular parallulopipeda. In this state the wood is brought 

 to the boring machine, which may be thus described (the lower figure 

 representing the plan, and the upper a side elevation) : 



The rectangle A B c D represent* the surface of a strong table, on 

 which is fixed an iron frame K having three legs ; within these the 

 parallelepiped r is placed Iwtween three screw-heads, two of nliich 

 appear at a a, and it is rendered immoveable during the operation l>y 

 means of the screw b ; this lost being turned by the iron bar on. r it 

 is one of the borers, which turns on ite axis by means of the pulley K, 

 the Utter receiving motion from the engine : this borer rents on the 

 frame M N, which is capable of being moved towards the frame 

 by pressing on the end r of the lever p q, so as to turn it about 

 the pivot q. h t ia another borer, which turns on ite axis by means 

 of the pulley B, the latter also receiving motion from the engine: 

 this borer rests on the frame 8 T, which is capable of being moved 

 towards the frame E by pressing on the handle u v, so as to turn it 

 about the pivot v. 



The former borer makes the hole for the pin I>M hii-h the sheaves 

 of the block are to turn; the other merely makes a pn !']. .nu at .-i 

 ]>.it which in t<> form one fxtrnnitv of tin- m.Ttis.- int<-mliil In onitain 

 a sheave. If the Mock u to contain two or three sheaves, the' l.,n , r i- 

 to make as many ) T Ix-in^ r.ip.ii>lr of i 



in a direction parallt-1 t.. u n. in order that the point of the borer mny 

 be placed where the required perforations are to be made. 



i.ukaMy ingenious machine is employed to cut the 1.1 

 in which the pulleys are to turn ; and it is hoped that tli<> following cut 

 and description will suffice to render the procccii intelligible. A B is n 

 represent. iti' n "f the horizontal surface of the table or stage on which 

 '!,'. Uck U placed ; and the diagram above it exhibits a side elevation 

 of the acting part of the machine, the pillars and braces which support 

 it being omitted, as they would have concealed, in part, the apparatus, 

 a a is a frame made to contain the block h which, in the diagram, has 

 I. tit one mortise ; the block is tightly fitted in this frame by means of 

 the screw t at one extremity, and the frame is capable of being moved 

 along the stage from i towards (f, as much as the win. I- 1. n^.li "f tin- 

 intended mortise. The great screw c D is fixed at one extremity to 



