Peter King probably knows more about historic British iron works than anyone
else.  He posted this to the arch-metals list.  I pass it on.

I did not even go into the difference in the buildings.  I assumed that your
question concerned only the main structure.  But what Peter says is certainly
true.  There would be a lot more "building" associated with a blast furnace.
There would be some kind of casting floor with a roof.  The blowing house or
bellows structure would be much larger.  It would not be unusual to find that a
blast furnace had a finery forge and smithy built as part of the same complex.

The geographic location would also be different.  Until such time as powered
lifts were available to load blast furnaces, they would have been built against
the side of a hill so that the charge could be wheeled to the top of the stack
across a bridge.  To some extent location would be a dead give away.  I can
think  of no compelling reason to build a bloomery against the side of a hill.
That doesn't mean that there aren't some that were.

Jamie

Peter King wrote:

> I feel that I am picking up the fag end of a conversation in replying to
> this.  However the most obvious difference is that a furnace will have a
> stack, a block of masonry at least five metres square.  Typically there will
> be buildings on a three sides of the stack, a blowing house, a casting
> house, and at a higher level a bridge house at the level at which the
> furnace was charged.
>
> Being in England I have not seen a 19th century American bloomery, but I can
> describe an English one of about 1720, Stony Hazel in north Lancashire.  The
> site has been excavated but has never been properly published.
> Unfortunately such publication as there is describes it as a finery forge,
> which is in direct opposition to the documentary evidence.  This is quite a
> modest single room structure.  The excavator found a bin with ore in it in
> the corner.  It had a single hearth and a single hammer, presumably each
> driven by a waterwheel.
>
> I assuming that some American bloomeries were of a considerable size and
> were permanent structures.  If so,  there would have to be some means of
> extracting the bloom.  This would require a large aperture in the side of
> the furnace.  A blast furnace's output is molten iron (and slag) and the
> forehearth is relatively small.
>
> It is difficult to deal with this subject in the abstract.  Would it be
> possible to describe the remains whose interpretation is in doubt?
>
> Peter King,
> 49, Stourbridge Road,
> Hagley,
> Stourbridge
> West Midlands
> DY9 0QS
>
> telephone 01562-720368
> ----- Original Message -----
> From: James Brothers <[log in to unmask]>
> To: Peter King <[log in to unmask]>
> Sent: 21 April 2003 17:20
> Subject: Re: Bloomery vs Blast Furnce