Friday, early afternoon; March, 19, 1830;

Chemistry lecture hall;

Ecole Polytechnique
.

At 51 years of age, his wavy brown hair streaked with gray, the highly-reputed and popular chemistry professor, Joseph Louis Gay-Lussac showed himself to be remarkably spry and even animated for his age as he delivered yet another of his appointed lectures at the Polytechnique to a mixed group
of science and engineering students arranged before him.
Restlessly strolling from one side of the lectern to the other,
occasionally glancing at his notes on the stand as if he were preferring to 'spy' on those present to see if they were 'drinking in his words' he affirmatively drove home some final points and facts on the subject of chemistry to his increasingly restless & weary
students before pulling out a watch on a chain from his long coat to see how much time he had left.
Out of habit he canted his wire-framed bifocals as he momentarily pondered the hour-hand on his watch, his upturned shirt collar keeping some of the students from observing his expression for a second or two.
"Well?" he signed in satisfaction, "I have less than ten minutes left in my lecture time to answer any of your questions. Do you have any? Remember you have vitally important written examinations awaiting you next week.
Please study your notes over the weekend."
Charles-Philippe was given an encouraging nudge by his blonde-haired friend and fellow student, George-Richard Marchand who was sitting next to him.
"Come on! Raise your hand!" he whispered
to Charles, "I know you have questions you want to ask him!"
Charles-Philippe complied hesitantly, raising his right hand almost timidly. The esteemed lecturer was quick to spot him; a look of
immediate recognition dawned on his face.
"Well, Monsieur Valcour! What questions do you have to ask me today? You usually have more than one."
Some restrained chuckles were heard coming from the lecture crowd at that last remark.
Charles knew that the esteemed chemistry professor grudgingly admired his inquisitiveness and his usually intelligent queries.
"Professeur! I want to ask if it would be practical to use acid gases, specifically, the possibility of using fixed air for operating piston and cylinder engines, like the
steam engines in use today? but without the need of boilers and fireboxes?"
Gay-Lussac slowly, thoughtfully took in a deep breath trying to conceal a condescending smirk
by jutting out his already prominent strongly-set jaw. He responded with
a touch of subtle humor,
"Young man! I thought you would ask me a chemistry question. It sounds to me like you are asking me a question regarding physics or mechanics. If so, you should be attending my physics lectures at the Sorbonne."
That reply generated a healthy dose of laughter from many in the audience. Charles squirmed slightly, retorting, "I affirm that it was indeed a question that does involve chemical reactions, professeur. If you were to produce fixed air by dissolving chalk by means of muriatic acid in some kind of strengthened or braced container or vessel you can
release sufficient quantities of fixed air that would produce enormous internal pressure comparable to that of steam within a steam-engine boiler; don't you agree, professeur?"
The renowned scientist and lecturer
eyed the young man warily with a hint of
annoyance.
"Monsieur Valcour! You're now asking a rhetorical question! " Gay-Lussac mildly scolded him, "And since you do not require my response as a chemist, I will
favor you with my response as a scientist in general; one with varied interests, including practical ones. So bear with me a little."
Charles attempted to protest but restrained himself to allow the distinguished lecturer to continue.
Gay-Lussac gestured to the other students present, "Among these fellow students of yours, Monsieur Valcour, are those
going on to earn degrees in engineering. At some time in the future some of them will be involved in the design, building and operation of a variety of machines, engines and devices.
They already know that, in theory any reasonable fluid under pressure would cause a
a piston & cylinder engine to function.
The questions then become: how long will it function? And how well will it function?
Let's suppose that one-hundred kilograms
of chalk are to be dissolved by the acid in question inside a - - - gold-plated or wax-lined storage compartment of a theoretical acid-gas engine. If the ratio between the acid and the chalk are ideal, and assuming that the acid is refined to a high-degree of purity, all of the fixed air
from the dissolute chalk and acid within a matter of perhaps - - a minute, maybe two, maybe three. You can see one of the obvious disadvantages such an engine would have compared to a steam engine...."
A slightly condescending smile worked itself across Gay-Lussac's face. There was a hint of regret with it.
"...That would answer the first question. As for the second question your assumption raises? I would answer it by saying that while indeed high-pressures, and with it, suitable power would be generated by the release of fixed air, there would also be a grievous liability involving the presence of acidic fumes that would attack and corrode gauges, pipes, cocks and the piston and cylinder.
Gold plating would help I suppose, but the expense! - - - And then the residual acidic fumes, as well as the asphyxiating fixed air would have to be vented from the cylinder, to the detriment or at least to the annoyance and discomfort of any man or men operating such an engine."
Charles-Philippe nodded reluctantly, mildly chastened. He however was not surprised by his chemistry professor's response.
"Thank you for your reply, professeur."
Gay-Lussac, once more pulled out and fleetingly glanced at his chained watch,
and then swept his eyes once more over his audience.
"I have a few minutes left. Any more questions? preferably genuine chemistry questions?'
he asked, seeing no one else but Charles putting up his hand. Gay-Lussac grunted
in chagrin.
"Very well. You have another - - - question,
Monsieur Valcour? Hopefully one that is not rhetorical?"
Once more Charles nodded, and shuffling some papers accompanying him, he asked,
"Professeur! Everyone here knows that gunpowder contains
saltpeter. And we all know that saltpeter contains the vital combustion element, oxygen.
But, when the other two ingredients of gunpowder are pounded and ground into powder and mixed, the powdered sulfur and charcoal will have oxygen atoms from the surrounding elastic fluid in close proximity, mingling with them. So my question is - - - will gunpowder explode if two of the ingredients, powdered sulfur and charcoal are not mingled with the oxygen from the surrounding elastic fluid? I pose the question under the assumption that the oxygen bound up in saltpeter may require more than a spark to release it."
The professor looked slightly but pleasantly surprised.
"That is a good question, young man." he
admitted thoughtfully,
"I would conjecture that the oxygen contained in the elastic fluid surrounding us would only be a minor source of that element necessary for gunpowder's rapid process of combustion to take place - - - and I think that indeed a spark would be sufficient to release the element oxygen bound up with, even bonded to the elements potassium and nitrogen in saltpeter to produce the rapid oxidization in any gunpowder mixture. Of course any such conjecture would demand experimental proof - - - perhaps by preparing and mixing the gunpowder ingredients in a vacuum."
Charles grinned.
"A vacuum such as can be created in a bell jar, professeur?"
the 20 year old chemistry student
commented rhetorically.
The professor nodded in wary agreement, hesitantly responding,
"Of course there is the potential peril of attempting to detonate gunpowder contained within a bell jar. If the quantity of gunpowder
should happen to be too large the bell jar may shatter into numerous shards of glass that would fly off like shrapnel or grapeshot."
For a second there was awkward
silence in that room; then Charles spoke out once more.
"I volunteer, professeur, if you need any assistance to set up and carry out such an experiment between semesters this summer, even if it requires modifying or making new apparatus! And I'm willing to take the risks!"