Christman's Patent

Charles Christman was a brass and woodwind maker, flourishing in New York in the period 1823 to 1858.  What brings him to our attention is a patent he lodged on Christmas Day 1849 (Christmas Day became a public holiday about 8 years later).  While the subject of the patent might be regarded more as a collation of good ideas from elsewhere than bold new work, it still gives us some hints about the state of the ordinary flute at the time and of the improvements that at least some were hoping to see in them.

I have taken some liberties with layout and punctuation to make the text easier to follow.  Any comments of mine will be enclosed [in square brackets].




Specification of Letters Patent No. 6,968, dated December 25, 1849.

To all whom it may concern: 

Be it known that I, CHARLES G. CHRISTMAN, of New York in the county of New York and State of New York, have invented a new Improvement in Flutes; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the annexed drawing, making a part of this specification, in which -

  • Figure 1 is perspective view of the flute.

  • Fig 2 is a section of one of the double keys.

[I have added a third figure - a detail of the combined Eb/D# keys referred to in the text.]

My invention consists in certain improvements in the musical instrument called the flute whereby certain notes are produced which are wholly unknown in the old instrument and secondly, the improvement in the quality, power and significance of certain other notes which, although produced on common flutes are yet of a very defective and unsatisfactory character. It is well known that there is a very great drawback in the pleasure derived from playing of hearing this popular instrument which arises from the fact that previous to my improvements, in almost every key it is out of tune, as for instance the E and A holes on the old flute are known to produce very poor, weak, and indistinct notes, whereas in my flute, these notes are full, clear, and powerful, and as satisfactory as the best notes formerly produced. 

Secondly, it is well known that in ascending and descending it is perfectly impossible to produce perfect semitones both ways, on the old flute, as for instance D sharp and E flat, G sharp and A flat, A sharp and B flat, whereas by my improvements I am enabled to give the variations required to sound these with as much delicacy and perfection as they can be produced on the violin, so that I have the power to give all the various shades of pitch (enharmonics) requisite to give the major and minor chromatic scales in perfect tune.

[Interesting that at this relatively late date in the US, and with Equal Temperament snapping at his heels, Christman is still looking for enharmonic solutions.]

My flute is constructed as follows. In Figure 1 is a view of the flute; the piece having the embouchure is omitted as that is of common construction, also are omitted several keys which are of like common construction, and are employed by me as in the old flute - these I have omitted to avoid complexity of parts in the description.  My flute is made generally after the ordinary manner, using for the purpose materials well known.

1, 2, 3, 4, 5, 6, represent six holes common to every flute, and it is by opening and closing these in various combinations that the successive sounds or notes are produced, but in some of these combinations very imperfect notes are given, as in the notes E and A, which are produced by the third and sixth holes. 

The manner in which I improve the tone of these notes is by changing the position of the holes by which they are produced and removing them a greater distance down the flute, thus widening the spaces between them and the next nearest hole, and reaching the said holes by a key formed to be actuated by the finger at the place where the said holes were formerly put, and are commonly played as at (a, b). 

By this means these notes are given in full volume and perfection, a thing which could not be accomplished before, without great skill in execution, and then with much uncertainty.

[This is Siccama's solution, arrived at and patented some years previously.  Siccama's Diatonic flute was well known in the US with versions made by several makers including Christman.]

The next head of my invention consists in producing perfect semitones on the sharp and flat keys. It is well known that in a stringed instrument a certain length of string which produces D sharp will require a slight variation in length to produce E flat, or any other sharp and flat.  Although in ascending or descending by semitones, both notes are indicated at the same place. In the violin and kindred instruments the difficulty is easily met by a slight shift of the finger, but in instruments where the notes are arbitrarily fixed, the difficulty is not so easily overcome, and in many instruments cannot be at all. This was the case with the flute, until I overcame it by the device I shall now describe. 

At the point (c) is produced on the old flutes, by one key, the notes D sharp and E flat, now as is well known these notes were never perfect but discordant. In order to make this part perfect, I produce two holes, as seen at (c, c',) Fig. 2, one of which holes shall be larger than the other. 
These I then cover with a double key (c, c',) Fig. 1 and construct them by interlocking their handles or operating ends, so that (c') can be worked without the other, but so that (c) cannot be operated without also opening (c'). Now by opening (c') a perfect E flat is sounded, and by opening the combined keys (c, c',) D sharp is given. 
At (d) and (e) are placed two more sets or keys covering pairs or holes on the same principle as those at (c, c',). These are for producing the notes G sharp and A flat, and A sharp B flat. 

[On first glance, the arrangement is reminiscent of Quantz's enharmonic Eb and D# key pair.  There is a difference though - in Quantz's arrangement you pressed either Eb or D# for whichever note you wanted.  In Christman's proposal, pressing one touch gave you D#.  Pressing the second touch opened both keys, converting the D# into Eb.]

In operating, E and A keys are fixed in range with the range of the six holes, upon the top of the keys, finger joints are placed over the part usually indicating those notes in the old flutes, as seen at the letters (a) and (b), thus rendering the fingering part easy of accomplishment.

What I claim as my invention and improvement and desire to secure by Letters Patent is:

  1. Removing the third and sixth holes from their ordinary place on the old flute to a point farther down, and sounding the notes produced by the said holes by keys operated at the natural fingering place, thereby producing with ease a quality of tone, now unattainable, or attained only by great skill, and then with uncertainty.
  2. I claim producing the true sharp and flat keys by means of the double holes and operating keys, as described herein.


Witnesses: S. H. Maynard, J. P. Pirsson.


I suspect that this was a patent to secure an idea, not a worked-out prototype.  Firstly, there appear to be no surviving Christman flutes that match the specification in this patent document.  So it's moderately likely that he never actually made one.

Secondly, isn't there a flaw in the notion?  It appears that the instrument, properly constructed, could give well tuned enharmonic notes for D# & Eb, G# & Ab, and A# & Bb.  But that's only three enharmonic pairs out the whole octave.  Where are the enharmonic options for the notes produced by the open holes?   Unfortunately Christman doesn't address this issue or provide a fingering chart to illustrate his intentions.

Christman mentions that his flute could have the usual other keys, but doesn't mention whether they also get the enharmonic treatment.

I'd have to say I'm dubious about the whole enharmonic note discussion (here and elsewhere), at least where it applies to flutes.  While fingering charts exist that show enharmonic alternatives (eg Nicholson's), a few minutes with a flute from the period will show that the tuning of the flute is so extremely erratic that the subtle variations between enharmonic alternatives are thoroughly swamped by the general deviations.  Typically, instead of giving say G# and Ab, the fingerings illustrated will give G# and G not so sharp.  In other words, instead of giving a pair of notes balanced around the Equally Tempered compromise, both will be on one side of it, and sometimes rather a lot to one side.  Frankly, when we hear a performance on original instruments with tasteful "notes sensible", we are hearing the mastery of the artist, not the maker.

Indeed, the paradox would appear to be this.  The best way to permit a flute to play enharmonically would appear to be by tuning it fairly closely to Equal Temperament.  The ET semitone (1.0594) lies between the narrowest (1.0417) and widest (1.0667) semitones used in just intonation.  Thus tuned, the player has the best chance of humouring the tuning to suit the key being played.

[I'll be pleased to back away from this bold statement, but only when I see a scale that balances the enharmonic notes moderately evenly around the ET scale.  Arguing that a good player can force them into position is not the evidence I need.  That simply reminds us of the extraordinary skills of some players.]

So is Christman's Patent document a waste of space?  No, I don't think so.  It serves to remind us yet again that, according to musical sensibilities at the time, the ordinary 8-key flute was unsatisfactory in tuning and in the equality of tone quality on different notes.  The romantic modern argument that "they liked it like that" simply does not stand up.  The only writers from the period who "liked it like that" were those promoting their most recent invention.  A few years later, their flutes would be condemned with all others.

And it does advise us that enharmonic aspirations still existed on Christmas Day in 1849 in the US of A, even if we were no closer to achieving them on our favoured instrument.  Even as the presses rolled on Christman's Patent, Boehm's new cylinder flutes were rolling out from Munich, London and Paris and would soon reach New York.  Enharmonics were doomed.


Special thanks to Jack Bradshaw, Physicist, Hampstead, NH, USA,, for bringing the existence of the Christman Patent to my attention.

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