\DeclareFixedFootnote{\BrKingNotesxMW}{\BrKingNotes{}, 69}

\section{The (Single) Musical Glass}

\subsection{The (Very Basic) Physics of the Singing Wine Glass}

Before delving into the history of the singing wine glass per se, let's understand the singing/musical wine glass a little better. 

Essentially a singing wine glass (or armonica cup) is a glass bell. Like a conventional bell made of metal, it has a resonant frequency, and if energy is put into the bell somehow\EmDash{}by striking it, for example\EmDash{}it resonates at its resonant frequency. 

When you rub the rim of a wine glass with a wet finger, you're doing the same physics as a violin player sliding the bow over the string\EmDash{}the 'sticky' bow pulls the string to one side of the violin until it slips, and the bow is able to catch it and pull it again. This process repeats itself over and over hundreds if not thousands of times a second. The exact same process occurs when you rub your wet finger around the rim of the wine glass: your finger 'sticks' to the rim and torques the glass until it finally slips, until your finger is able to catch it and torque it again. This process repeats itself over and over (again, hundreds/thousands of times a second), which puts energy into the (glass) bell, whose physics only allow it to vibrate at musical frequencies. And, voil\`{a}! A musical sound!

The standard wine glass is ideal for this because the stem gives the player something to hold on to while their wet rubbing finger puts energy into the bowl: if the player holds the bowl (bell) itself, this prevents the sides from vibrating\EmDash{}and thus no musical sound.

Adding water lowers the pitch (which the reader can verify for themselves in their own kitchen) mostly because\EmDash{}in effect\EmDash{}it adds mass to the sides of the glass, effectively making the sides heavier and thus lowering the pitch of the glass.\footnote{The water also adds a compressive factor that additionally complicates matters. See Chan.}

% ??? FIGURE
 
Putting water inside the wine glass lowers the pitch, and so does putting water outside of the glass! Take a wine glass and check its pitch (with the wet finger around the rim); then run some water in your kitchen sink, put the glass in the sink so the glass is submerged except that the top part of the bell is above water, and check its pitch again. (See the figure below). Partially submerging the glass lowers the pitch.
 
In fact, having water both inside and outside of the glass lowers the pitch most of all. The reader can verify that adding water 'outside' the glass also lowers the pitch by placing a wine glass in a sink partially filled with water.

To recap: two essential elements are required for a musical glass: the walls of the bowl must be thin enough to vibrate easily, and it must have a stem\EmDash{}so the player can hold the glass by the stem without dampening the vibration of the bowl. You need both\EmDash{}thin-walled bowl, and a stem\EmDash{}or the wine glass simply will not sing with the wet finger around the rim.

Neither the Romans nor their Byzantine successors particularly cared about blowing thin glasses. But that was a hallmark of the Venetian glass blowers of the 14th through 16th centuries\EmDash{}particularly due to their invention of \textit{cristallo}. These glasses were available to the wealthy throughout Europe. 

\subsection{Shattering a Glass with the Voice}

We have seen how a Venetian wine glass can be shattered by placing poison in it (and how there may actually be some truth to it). In addition, if a glass is subjected to a sufficiently loud sound at exactly its resonant frequency, it will shatter it. 

Scholes\footnote{\BrScholes{} 7} mentions a book by one D.G. Morhof `on an Amsterdam tavern-keeper who could vocally shatter twenty-five glasses in thirty minutes'. And the \Title{Talmud} (the compilation of Jewish civil and religious law completed A.D.500) says:
\begin{quote}
When a cock shall stretch forth its neck into the hollow of a glass vessel and sing therein in such a way as to break it, the full loss shall be paid.

When a horse neighs or an ass brays and so breaks a glass vessel, the half of the loss shall be paid.
\footnote{Soncino edition (London, 1936), Kiddushin, p.118 \TODO{???}}
\end{quote}
This is of course academic legalism\EmDash{}it's hard to imagine such incidents actually occuring. But it shows that they were aware of the possibility of shattering a glass with sound.

A rather curious sequence of articles appeared in the London \Title{Times} and other London papers in 1947. On February 3, 1947, `The Times' printed a letter raising as a legal issue possible damage to a person resulting from the fragmentation of a glass, when, on January 18, a `lady of pleasing voice was singing a beautiful aria in ``Madame Butterfly"''. The `Evening Sandard' in its issue of that same day went on to say that the note in question was the top B flat of `Un bel di', sung by Miss Josie Fearon.

n the next few days `The Times' printed a selection from many letters received on this subject, giving instances of the shattering of a glass by causes ranging from the voices of Clara Butt, Lablache, Garcia and Caruso, to the shrill chatter of children and the tones of a schoolmistree teaching Greek! As a kind of follow-up, the `Sunday Express' printed the following letter on April 27, from a lady in Upminister:
\begin{quote}
Shortly after my brother drank from a glass, Lassie, our Devon sheepdog, gave a piercing bark in the yard below. The glass exploded, fragments shootng all over the room.
\end{quote}\footnote{\BrKingNotesxMW{}}
Maybe the \Title{Talmud} was right about barking dogs and glasses after all!

A Hyatt King repeats an even more bizarre story by the then editor of the `Strand Magazine' who recalled that in 1898 it had published a story `The Luck of Pitsy Hall'\ldots

\begin{quote}
\ldots in which the villainess plotted to shatter a valuable goblet at a coming-of-age ball given for the Pitsy heir. She secured an orchestra to play a waltz of her own composition into which she had cunningly introduced a malignant sequence. For a repeated unison on the dominant broke the goblet by a purely acoustic agency which its guardin footmen could hardly have forestalled!\footnote{\BrKingNotesxMW{}}
\end{quote}

% \TODO{???} glass of poisoned wine explodes 'Mysteries of Udolpo' see King (1956) p.69