You may recall a scene in Patricia Rozeman’s adaptation of Mansfield Park where we see Julia and Maira Bertram playing a strange instrument for the entertainment of the family . Here is a scene cap from the film showing them  at work:

They were, in fact, playing a glass harmonica.

This is a fascinating instrument which was invented by the American polymath, Benjamin Frankin in 1761 while he was living  in London. He had heard Edward Delaval , a Fellow of the Royal Society, play on his set of musical glasses in 1759. This was an idea with which we are more familiar, I think , as we can still see these types of glasses played today by some variety artists. In fact these glasses -wine glasses filled to different levels with water which were played by rubbing wetted fingers along the rims- seems to have been the  brain child of a Mr Puckeridge of Ireland,  but he and his glasses perished in a fire. Edward Delaval was fascinated by the properties of glass and he studied the specific gravities of several metals and their colors when bonded with glass, and also how to use it in the manufacture of artificial gems, hence his interest in this instrument. Benjamin Franklin improved upon his idea- of the rows of glasses fitted in a cabinet, by creating a very different instrument.  Here is his design from the modern exponent,  Thomas Bloch’s fascinating website:

You can see that it is quite radically different: scores of glass bowls are nested within each other, strung centrally on a spindle that spins, and which is turned by means of a treadle.  Here, below,  is a late 18th century version in its wooden cabinet, with a handle to turn the glass bowls, not a treadle:

Here is a photograph of  Thomas Bloch’s  own glass harmonica, which shows the position of the players hands when operating the harmonica :

Frnaklin’s instrument was so improved that it  transformed the performance aspects of the harmonica. Now duets could be played,as in the adaptation of Mansfield Park, and individual players could now play chords .If you go here you can see the example in London Horniman Musuem which was used in the linked BBC Radio 3 programme below.

This was not an  instrument that could be enjoyed by everyone: it was very expensive to produce  and buy and needed very specifically trained teachers. Mozart was a fan and wrote some beautiful music for it. It was used by Mesmer as part of his electronic experiments, to soothe his patients. But this reputation for celestial soothing music was not long lived. One of its most famous exponents was the blind German-born woman, Marianne Kirchgessner, and she was famous for giving concerts on the instrument throughout Europe. She was rumoured to have been driven mad by playing the instrument, but this was probably not due to its strange sound( which I confess I can only listen to for very small intervals as it makes me grind my teeth!) but to lead poisoning. Playing with whetted fingers on glass that had high lead content most probably contributed to her demise.

Modern composers have use the instrument to great effect- in film scores and in rock music; Pink Floyd’s Dark Side of the Moon, for example. If you would like to know more of the history of this fascinating instrument  you might care to listen to this fabulous BBC Radio 3 programme, presented by Dame Eveyln Glennie, one of our most distinguished percussion players, shown below.

If Chimes Could Whisper is a short (45 minutes long) but totally enthralling history of the Glass Harmonica and contains a lot of examples of the instrument being played- pieces of music which date from the 18th century to the present day.

If you click on the link above you should be able to access the webpage linking got the programme which is available to “listen again” for another five days.

Alternatively here, above, is a video of Thomas Bloch playing his  fabulous glass harmonica, which I’m sure you will enjoy. It is a very evocative sound. How appropriate that the Miss Bertrams were portrayed playing  such an instrument; expensive, exclusive, seemingly celestial but with hidden dangers ;)