John William Draper

The Man Who Photographed the Moon and Lit the Spark of American Science

"The history of Science is a narrative of the conflict of two contending powers, the expansive force of the human intellect on one side, and the compression arising from traditionary faith and human interests on the other." ⁴

A Polymath in a New World

In an age of specialists, John William Draper (1811-1882) was a breathtaking exception. A physician, chemist, physicist, historian, and pioneering photographer, his curiosity knew no bounds ¹ ³ . His life and work unfolded like a microcosm of the 19th century's intellectual fervor, bridging the gap between the elegant experiments of the natural philosopher and the bold, institutional building of modern science.

Photographic Pioneer

Made some of the first photographic portraits and captured the first detailed image of the moon ¹ ⁵ .

Scientific Leader

Served as the first president of the American Chemical Society and founded the New York University School of Medicine ¹ ³ .

The Dawn of Scientific Photography: Capturing the Invisible

Before the advent of digital sensors and instant images, Draper was mesmerized by the power of light to create permanent chemical change. He wasn't merely a technician of the new daguerreotype process; he was a scientist who saw it as a powerful new tool for investigation ² . His work moved photography from a novel art form into the realm of rigorous science.

The Grotthuss-Draper Law

One of Draper's most fundamental contributions was his clear enunciation of a principle that would become a cornerstone of photochemistry. In 1842, he demonstrated that only light that is absorbed by a substance can produce a chemical change ¹ ² .

The Tithonometer

Ever the inventor, Draper needed a way to quantify the chemical intensity of light. His answer was the tithonometer, the first device capable of measuring the amount of light absorbed in a chemical reaction ² ³ .

Draper's Research Toolkit

Item	Function in Draper's Research
Silver Halide Salts (e.g., Silver Iodide)	The light-sensitive heart of the daguerreotype process ³ .
Hydrogen & Chlorine Gases	Used in his tithonometer to measure the chemical intensity of light ² .
Prism/Spectroscope	Used to split sunlight into its constituent colors (spectrum) ² ⁵ .
Mercury Vapor	The "developer" for daguerreotypes ¹ .
Telescope	Served as a long-focus lens for his astronomical photography .

A Landmark Experiment: The First Astrophotograph

In the winter of 1839-1840, just months after the daguerreotype process was announced to the world, Draper turned his camera from the earthly to the celestial. His successful attempt to photograph the Moon was a watershed moment, marking the birth of astronomical photography ¹ ⁵ .

Experimental Methodology

Polishing and Sensitizing the Plate: A silver-plated copper sheet was meticulously polished and sensitized with iodine vapor ¹ ² .
Aligning the Telescope: The sensitized plate was placed in a camera affixed to a telescope .
The Long Exposure: Required a full twenty minutes to capture enough light ⁵ .
Developing the Image: The plate was developed using mercury vapor ¹ .
Fixing the Photograph: The image was made permanent by washing the plate ¹ ² .

Key Parameters

Object	The Moon
Date	Winter 1839-1840
Exposure Time	~20 minutes
Image Size	~1 inch in diameter
Technique	Daguerreotype

Early photographic equipment similar to what Draper might have used for his moon photograph

Beyond the Laboratory: A Legacy of Ideas and Institutions

Draper's intellectual energy was not confined to the lab. In the latter part of his career, he turned his focus to history and the sociology of knowledge, producing works that ignited public debate and left a lasting, if contentious, impression ¹ ³ .

His most famous and influential book, History of the Conflict between Religion and Science (1874), argued that the progress of science had been perpetually hindered by the dogmatic opposition of religious authority, particularly the Roman Catholic Church ¹ ⁴ . The book was a runaway bestseller, translated into nearly a dozen languages, and it popularized the "conflict thesis," which framed the relationship between science and religion as inherently hostile ¹ .

Alongside his role as a public intellectual, Draper was a nation-builder in the world of American science. In 1876, when Charles F. Chandler and others sought to establish a national professional organization for chemists, they chose Draper as the first President of the American Chemical Society (ACS) ³ . His name and prestige lent immediate credibility to the new society, helping to launch what would become the world's largest scientific society ³ .

Major Honors and Institutional Roles

Honor/Role	Year	Significance
President, NYU Medical School	1850-1873	Provided leadership for one of the premier medical institutions in the country ¹ .
Rumford Medal	1875	Awarded by the American Academy of Arts & Sciences for his research on radiant energy ¹ ³ .
First President, American Chemical Society	1876	His leadership helped establish a national professional identity for American chemists ³ .
Elected to National Academy of Sciences	1877	Recognized his standing among the top American scientists of his generation ¹ .

Draper's Life and Achievements

1811

John William Draper is born in St. Helens, Lancashire, England.

1839-1840

Makes the first successful photograph of the Moon, marking the birth of astrophotography ¹ ⁵ .

1842

Formulates the Grotthuss-Draper law, a fundamental principle of photochemistry ¹ ² .

1850-1873

Serves as President of NYU Medical School ¹ .

1874

Publishes History of the Conflict between Religion and Science, which becomes an international bestseller ¹ ⁴ .

1875

Awarded the Rumford Medal for his research on radiant energy ¹ ³ .

1876

Becomes the first President of the American Chemical Society ³ .

1877

Elected to the National Academy of Sciences ¹ .

1882

Dies in Hastings-on-Hudson, New York, leaving behind a profound scientific legacy.

Conclusion: The Expansive Force of an Intellect

John William Draper's life reminds us that the pursuit of knowledge does not need to be confined to a single discipline. From the silver-coated plates of his moon photographs to the printed pages of his historical texts, he consistently sought to capture and understand the forces that shape our world—both physical and intellectual.

His pioneering work in photochemistry and astrophotography provided new tools for science, while his leadership helped forge the institutional frameworks that would support future American scientists. Though some of his historical ideas have been re-evaluated, they undeniably stimulated crucial public conversation about the role of science in society. Draper was, in every sense, a catalyst—an individual whose own energetic inquiries accelerated the reactions of progress and thought around him. His legacy is a testament to the power of a truly inquisitive mind, forever looking to the light.