CHARLES AUGUSTUS SCHMALCALDER

INVENTOR OF THE PRISMATIC COMPASS

March 5, 2012
200th anniversary of the filing
of Schmalcalder's Patent



Charles Augustus Schmalcalder registered Patent N° 3545 on March 5, 1812 under "Philosophical Instruments" and was granted an "especial licence" by His Majesty King George III, which had a duration of fourteen years.  The Patent expired on March 4, 1826.

Charles Schmalcalder was born on March 29, 1781 in Germany as Karl August Schmalkalder.  He Anglicised his name when he moved to London.  He worked from 1806 until1840 when he was recorded ill with disability and living in The Strand Union Workhouse, Castle Street, St. Pancras, London, where he died on December 25, 1843 in London, aged 62. He is recorded as having been buried in The Strand Union Workhouse cemetery. It would seem that Charles Schmalcalder fell on hard times towards the end of his life, probably caused by illness, which prevented him from earning a living.

What is the "Schmalcalder Patent" ?  Schmalcalder was not known as a compass maker.... so what is it?  What is a Schmalcalder compass?

The Schmalcalder Patent refers ONLY to the folding prismatic sighting mechanism with sighting vane that appears on compasses.  It does not apply to the compass itself.  The compass had already  been "invented" when he filed his patent.  The Schmalcalder Patent was purely an "improvement" on the current state of the art.

The Schmalcalder Patent was undoubtedly the most important development in the history of compass making, with the exception of the original invention of the compass.  The design, patented in 1812, is still in use today, unchanged, on all of the world's finest prismatic compasses used by armies in nearly every country in the world.

How do you identify a Schmalcalder compass?  Any prismatic compasses signed "C. A. Schmalcalder" are very rare, and probably slightly pre-date the actual Patent. 

Compasses bearing the mark "Schmalcalder's Patent - 82 The Strand or 399 The Strand, London" were compasses manufactured under license, or to order by Schmalcalder, by third parties during the lifetime of Schmalcalder's Patent.  Schmalcalder was not known to have the ability to produce compasses in commercial quantities, so he would have done what all businesses did, and still do.... have them made by a "maker" on his behalf.  The address on the card refers to the Patent more than to the maker, but it is certain that compasses bearing the wording C. A. Schmalcalder, or Schmalcalder's Patent were produced to order by Schmalcalder, and certainly sold almost exclusively from his shop, either at 82 The Strand, or subsequently from 399 The Strand.  The hand-written signatures on the dial would certainly have been produced in Schmalcalder's own workshops.

It is interesting to note that all compasses signed "C. A. Schmalcalder” or "Schmalcalder's Patent" bear a sequential serial number.  All the compasses bearing the address 82 Strand, the earlier address, have the letter "B" as a suffix to the serial number (e.g. 291 B) and all compasses bearing the later address, 399 Strand, have the letter "C" as a suffix to the serial number (e.g. 2150 C).  I believe that compasses signed "C. A. Schmalcalder" may have carried the suffix "A" and may have been produced at his earliest known trading address in Soho, but have not been able to confirm this yet.  Serial numbers were always hand engraved on the base and inside the lid, and should match. 

After 1826 a number of manufacturers produced prismatic compasses in great quantities, signing their own names, as the patent had expired, and namely Troughton, Simms, Barker and many others.

Charles Schmalcalder did not appear to use brass lids for the compasses he actually signed "C. A. Schmalcalder".  The lid, however, appeared on all compasses signed "Schmalcalder's Patent".  The lid is clearly mentioned in Schmalcalder's Patent.

Charles Schmalcalder worked from his home at 6, Little Newport Street, St. Ann's, Soho, London, from 1806 for some years.  By 1812, when he filed his Patent Application, he was working from The Strand, London.  C. A. Schmalcalder worked at 82 The Strand from 1810 until 1826, and from 399 The Strand from 1827 until his retirement in 1840. 
Charles Augustus Schmalcalder was succeeded by his son, John Thomas Schmalcalder (born 1811), who traded initially from his home, that his father had originally traded from when he started his career, in 6 Little Newport Street, Leicester Square, London, and then from 1841 until 1845 from 2 Fairfax's Court, 400 The Strand, London.

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Other theories exist, but they only differ slightly from mine.

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CLICK HERE TO DOWNLOAD SCHMALCALDER'S PATENT 

(6 PAGES IN PDF FORMAT)

The patent application is out of copyright so is free to use and circulate.

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Thomas Jones is officially documented as having traded from 62 Charing Cross, London, only between 1816 and the beginning of 1850.  The style of the compass below, and the red Morocco leather case is in the very earliest style of Charles Schmalcalder's production, and generally, around 1820, the red leather was replaced by brown.  This example also was manufactured without a brass lid, absolutely identical to one signed "C. A. Schmalcalder" that now resides in the British Science Museum in London, a poor quality photograph of which can be seen on the Schmalcalder Family website.   It is probable, given their proximity (a short walk in the same street), that Thomas Jones provided Charles Schmalcalder with the original compasses to which Schmalcalder added his patented prismatic sighting mechanism, as Thomas Jones did produce compasses identical to those used by C. A. Schmalcalder.  Later compasses with lids and bearing the Schmalcalder Patent signature were probably manufactured by Simms, Barker and various other prolific compass manufacturers.

Below, a Schmalcalder Patent compass, that has a lid,
marked 399 The Strand, London







Below: Photographs of a very early example of a "Schmalcalder's Patent" prismatic compass.  This one was manufactured by Thomas Jones of 62 Charing Cross - London, possibly under license from Charles Schmalcalder, as it is probable that Thomas Jones made compasses for Schmalcalder, or possibly shortly after the patent expired.


















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page updated 20 May 2011