B L O 



B L O 



with this f;rsat difcovcry and application of the art of cad- This was completely accomplifhcd by inverting large cherts, 

 ing, the blowing machine alTumed a general and udl-pro- or cylinders, in cifterns of wood, ftone, or iron. The fpace 



portioned form 



This took place nearly 40 years ago, and continued with 

 a few temporary deviations until the introduction of Bolton 

 and Watt's highly improved engine. The followiug may 

 ferve for an oiitHne of the old blowing Iteam engine. 



A Ifeam cylinder, working with atmofpheric prefTurefrom 

 3 to 7 lbs. upon every fquare inch of the area of the pifton. 

 The diameter of the cylinder for one furnace varied from 

 25 to 36 inches, and for two furnaces from 56 to 50 

 inches. Upon the oppofite of the main or working beam, 

 fomctimts at equal, and fometimes at unequal diftances from 

 the centre, was placed the air-pump or blowing cylinder, 



betwixt the inner and outer cifterns was conftrufted of fuf- 

 ficient capacity to oppofe to the expanfive force of the blall 

 a column of water of equal or fuperior refiftance. 



This invention was called the water blaft, water preffure, 

 water regulator, &c. The dimenfions differed materially 

 from from each other ; this circumftance being much regu- 

 lated by conveniency, opinion, and the fize of the engine. 



Plate XlV.Jig. I, {Chemijh-y) reprefents a ground plan of a 

 very capacious water regulator, funk in the ground, and built 

 of ftone and bricks. 



A, the inverted cheft made of plates of cafl iron, 40 feet 

 'ong, 12 feet v/ide, and 12 feet high. The fquare fuper- 



This was, in common, equal to four or five times the area of iicies of this cheft is equal to 4S0 feet, and its cubical con 



the former; and, with the fmall working power of the fteam 

 cylinder, feldom coiidenfed the air beyond i\ to if lbs. per 

 fquart inch. The air-pump was commonly conllruftid open 

 below, as may be feen in Phte II. fi-;. I. {Chemijhy). The 

 plan was fometnnes deviated from, and the cylinder inverted. 

 The blowing pillon was loaded with weights, and the air ex- 

 preffed by its defcent. In this mode of working, the act 

 of the fleam pifton, defcending in vacuum, railed the air 



tents are 5760 feet. Its weight will amount to nearly jo 

 tons. 



B, the opening to which the air-pipe is attached ; 2 feet 

 diameter. 



CCCC, open fpace betwixt the inverted cheft and ftone 

 ciftern, for the column of v/ater to afcend ; jf feet wide. 



D D D D, ftone or brick-work, of which the great 

 ciftern is built. This work requires to be well jointed, as 



pump pifton loaded with weights. Upon the return of the the motion of the water has a great tendency to open the 



ftroke, or while the fteam pifton afcended in the cylinder, this 

 pifton loaded with weights funk the whole length of the 

 ftroke, and by means of this loading, proportioned to the 

 powers of the engine, forced the air either into the regula- 

 tor or the furnace. 



Above, or parallel to the air-pump, was placed the regu- 

 lating cylinder, as may be feen in the plate above mentioned. 

 This had a valve of communication, which opened every 



fpaces betwixt the ftones. This ciftern is 47 feet ftct long, 

 19 feet broad, and 14 feet high ; its cubical meafurement 

 amounting to 1 2,500 feet, and capable of containing 93,300 

 gallons wme meafnre. 



e eee, an opening of one foot in breadth left in the 

 middle of the building. This is compactly filled with well 

 trod clay, called puddling, and prevents the efcape or circu- 

 lation of water through the building. Beyond this the 



ftroke the engine made, and admitted the whole difcharge common building extends to a fufficient thicknefs to give 



of air. The pillon of the cylinder, frequently called the general fecurity to the whole. 



fly pifton, was loaded with weights, and kept conftantly Fig. 2. is a crofs feclion of the water regulator at B, 



vibrating; fo that when any deficiency of preffure arofe fig- i. The letters in this view correfpond with thofe in the 



from the remitting aftion of the air-pump pifton, the blaft plaji 



was comparatively equalized by the prefture of the fly pifton 

 upon the included air. The fize of this cylinder was gene- 

 rally in the proportion of 9 to 6 of the air-pump. 



The chief objeftions to this mode of blowing, even when 

 in univerfal ufe, were founded upon the great inequality 

 of the blaft, and a very confidcrabie waile of air that took 

 place at iht/nort, or fafcty valve, to prevent the fly pillon 

 being blown entirely out of the cylinder. The fnort was 

 an opening made in the top of the air-pump cylinder, on 



F, the blaft; pipe from the cylinder entering the cheft, 

 and branching to the two blaft furnaces. 



G G, large hewn ftones, on which the cheft is fupported» 

 about two feet from the bottom of the ciftern, at inter- 

 vals of fix feet from each other. 



H, loading of hewn ftone, which for this ciftern requirei 

 to be equal in all to 90 tons. If the cheft weighs 30, then 

 60 tons of loading will be requifite. This is fuppoiing that 

 the power of the blovring machine is calculated to prefs 



which relied a heavy iron valve, faced with leather fluffed equal to 3 lbs. upon every fquare inch, which many of them 



with wool ; this was, by means of an upright iron rod, at- are conftrufted to perform. 



tached to a lever, which run acrofs the top of the regulating To comprehend diftinftly in what manner the water re- 



«ylinder. As foon as the fly pifton arofe to a certain height, gulator performs its funftions, and upon the fuppofition 



a block of wood, or other contrivance, lifted the one end that the comprefling power of the engine is equal to j lbs. 



cf the lever, and along with it the valve, to a certain height, upon eveiy fquare inch, we fhall fuppofe the engine at 



and permitted a quantity of the denfeft air to efcape, fuffi- reft, and water introduced into the regulator, till it rife to 



cient to infure the fafety of the pifton. Notwithftanding the level of the dotted hnc li, 5 feet from the lower edge of 



thefe precautions, many accidents and ftops enfued ; the the cheft, and 7 feet in total depth of water. As foon a« 



breaking of a pin, or the loofingof a key, frequently ejefted the engine is fet to work, the compreflion of the air imme- 



the pifton from its cylinder, though loaded with feveral diately fets the water in motion ; every ftroke making 



tons of weight. the water rife in the fpace CC, and proportionally falling 



Some iron matters, more ingenious than others, contrived towards GG, in the interior of the cheft. 



to take the fpare or wafte air from the fnort, to receive it in 

 An inverted chefl above water, and blow to its extent fmithy 

 and finery fires. Endeavours of this kind to hufbandand eco- 

 nomife air, raifed and condenfed at a great expence, were 

 fufficient proofs that a method was ftill wanting to complete 

 the blowing machine, to render its motions fteady and uni- 

 form, and toequahze the denfity of the blaft throughout the 

 \ivhole ftroke. 



When the inverted cheft becomes filled with air, and the 

 condenfation has reached the maximum of the power of the 

 blowing machine, the water will be found elevated 5* feet 

 to i, and the gauge will exhibit a depreffion in the interior 

 of the cheft, from /; to /, 3I feet, making in all 7 feet 

 from k to /. 



At every turn of the engine ftroke, the water maintained 



at < falls a few inches, and elevates itfelf above i in the in- 



4Mz luisx 



