Providence WaterFire, 1784

According to the website for Providence’s WaterFire, the summer event requires “hundreds of volunteers” devoting “thousands of hours”. But for residents of Providence in 1784, all they had to do was walk out to the river.
“Observations on the Luminous appearance of the River Water at Providence on the Night following the 16 of Sept. AD 1784″* is the title Thomas Truman gave to his brief account of that unusual night. He opens the story as follows:**

On the last evening I attended the philosophical lecture of the celebrated Dr. Moyers in which he discoursed on the nature and properties of phosphorous natural and artificial and among other matters he endeavored to account for the luminous appearance of the sea at certain times as noticed by mariners, particularly in times of boisterous weather.

Certainly conveniently coincidental timing. Truman continues his introduction by offering the Dr.’s opinion on the cause of the luminous appearance:

It was his opinion that this appearance was occasioned by putrid substances in the sea water.

Truman was a doctor (as well as a dentist, bookseller, scrivener and general merchant***), and on the night in question he was on his way home from a patient and discussing Dr. Moyers’s hypothesis with a fellow medical professional named Dr. Bowen. Not long after parting from his friend, he was called back by Bowen’s “young man,” who was sent to retrieve Truman:

When I came I observed a white luminous [streak on] the water extending from the bridge…
… it was so light as to shine through the bridge as much as though several candles had been under it.

At which point the experimenting began. Truman and Bowen first went to the steps beside the Market House and stirred the water with their canes, verifying that disturbing the water increased the brightness of the light. Phase two of the research:

We now got a basin and took up some of the water [and] upon stirring it with our hand it appeared full of small round particles of fire and gave considerable light [and] some of the firey particles adhered to the hand and remained unextinguished for several seconds.

The basin was then used to pour water out on the ground and then to splash it on the walls of the Market House (still standing after 235 years of abuse). But back to the central question: Is Dr. Moyers on the right track?

Suspecting that this appearance might be occasioned by some scum or filth mixed with or floating upon the water we got a light and found teh water perfectly transparent and colorless.

Worrying that their sample was too limited, the doctors next hired someone with a boat to bring back a dish from out on the water, which turned out to be just as clear.
The next stage of experimentation:

We took [a basin of the luminous water] to a pump of fresh water and filled the basin. This so far from extinguishing the fire seemed to increase it. The particles indeed were smaller but more numerous and were visible for more than a minute.

Onsite investigation having been exhausted, it was time to return to the lab:

We now procured some clear white vials, holding each about eight ounces, and filled two of them at the Market House steps, two at Mr. Chace’s Wharf, and one was sent to the lower end of the town to be filled there…. The vial sent down town was not returned.

Truman brought his vials home and retired to “a room so dark that nothing could be perceived” and proceeded to his tests. First he determined that shaking three vials made more light than shaking a single vial. The second discovery was one of the typical moments of scientific serendipity:

One thing I observed which was a little curious: there was in the dark room a bunch of asparagus hung up for the flies to light upon****, which were very numerous upon the vials [and] being shaken, so much light was produced that the flies took wing and made that humming noise which they usually do upon a candle being brought suddenly into the room where they are at rest.

Dr. Truman’s experimentations continued until 1:15.
The nineteenth century would see much more research and clarification of the type of  bioluminescence Truman observed that night. And it was curiosity like his that would make it possible.

* Truman Papers, Rhode Island Historical Society, MSS 762.
** Spelling and punctuation have been modernized.
*** Providence Gazette, 22 December 1781 and in 1784.
**** ?