VOL. XL.] PHILOSOPHICAL TRANSACTIONS, IQQ 



gutter, acquires the power of a falling body ; which power increasing in the 

 same proportion as the bellows to be raised becomes heavier, this power suits 

 admirably well the weight to be raised; for the bellows that sinks down into the 

 sump N, does not at once lose its weight in the water, but gradually as it de- 

 scends deeper ; and after the same manner the ascending bellows does not be- 

 come at once heavier than the other, but gradually, being heaviest just when 

 the lowermost edge gets even with the surface of the water ; and that happens 

 at the same instant of time jwhen the power of the water in the sloping gutter 

 is at the highest pitch, or has received its greatest momentum. 



This shows that the power required to work these water-bellows is far less, 

 and consequently less water will be consumed in working these bellows, than 

 those commonly used ; and again, that an iron furnace, which for want of water 

 to work the common bellows, cannot be kept at work longer than 6 weeks, 

 though it be provided with all other necessaries, may, by means of such water- 

 bellows as here described, be kept at work at least as long again. 



It is also known to miners, what great loss and inconvenience it is, when the 

 hearth or mouth of an iron furnace is placed low, in a wet and damp place, 

 which they are often obliged to be, in regard to the axle-tree of the water- 

 wheel which works the bellows ; for which reason such furnaces as stand in the 

 like moist places, give daily considerably less iron, than others which are better 

 situated. There is likewise no small difficulty in finding a fit situation for such 

 iron furnaces where iron guns are cast, and require deep pits under the mouth 

 of the furnace : but by means of this new invention of bellows, one may be at 

 liberty to place the mouth of the furnace as high as one pleases, as it is very 

 easy to guide the blast by means of wooden or leaden tubes, as far as necessary, 

 and in a proper direction into the furnace ; which advantage cannot so easily be 

 obtained by the bellows in common use. 



It may also be accounted as no small advantage which these bellows afford, in 

 being of so very easy a structure, that any carpenter at first sight is able, not 

 only to construct the whole engine, but easily to repair every part of it, re- 

 C[uiring at the same time the least repairs of any that can be used ; and if the 

 bellows should be cast iron, they would last for ages ; and when cast strong, 

 they would not require any weight to sink readily in the water. They might be 

 covered with lead, or be made of thin copper, with a thick leaden hoop at top, 

 to make them sink. As for their shape, it is not absolutely necessary they 

 should be of the same as the figure annexed denotes ; for if we would not 

 bestow iron hoops on the bellows, they might be made square, or triangular, or 

 any other shape, provided they be as wide again at bottom as at top; and when 

 made of wood, it will be necessary to provide an edge round the tops, for con- 



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