In 1874, an astronomer and an inventor together published one of the most influential books of the time on lunar geology, titled The Moon: Considered as a Planet, a World, and a Satellite. In 276 pages, James Nasmyth and James Carpenter summed up three decades of research encompassing all that astronomers knew about the moon, and even attempted to answer some of the still-unanswered questions of the time, such as: Could the moon support life? Did it have an atmosphere? How did its craters form?
Accompanying the text were a collection of striking photographs of the lunar surface, highly detailed and so up-close that they seem like photographs from the Apollo missions which wouldn’t fly for another century. While it is possible to take such detailed pictures of the moon today without leaving terra firma using powerful telescopes and modern cameras, back then photography was still in its infancy and there was no suitable technology to take photographs directly through a telescope.
So how did James Nasmyth manage to take these photos? By building accurate plaster models of the moon’s surface in meticulous detail guided by sketches he made by peering though his self-made telescope. He then photographed the models against a black background and with a strong light shining obliquely upon them to mimic the rays of sunlight hitting the moon’s numerous craters and mountains.
“The result is perfect; far more perfect than any enlargement of photographs could possibly have been,” wrote one of the book’s contemporary reviewers.
James Nasmyth may not have been a professional astronomer, but this Edinburg-born Scotsman was one of the leading engineers of his era. Son of a painter, Nasmyth showed an extraordinary mechanical inclination from a very young age. He was only seventeen when he made his first model steam engine, and twenty-one when he made a complete steam carriage capable of carrying half a dozen people. For two years, Nasmyth worked in the machine workshop of the famous inventor Henry Maudslay in London, but later moved to Manchester where he set up his own foundry business. Soon, Nasmyth and his business partner were making all kinds of heavy machinery for factories, for the railways and for steamships. While forging the unusually large paddle wheels of the steamship SS Great Britain, Nasmyth solved the technical challenges by designing the highlight of his career—the steam hammer. Although, the great paddle wheel for which the mighty hammer was invented was never hammered out, the steam hammer became such a huge commercial success that Nasmyth was able to retire comfortably at the age of forty-eight to pursue the other passions in his life, notably astronomy and photography.
Nasmyth settled down near Penshurst, Kent, where he built his own 20-inch reflecting telescope. Always an inventor, Nasmyth modified a typical Cassegrain telescope by adding a third diagonal flat mirror to pass the beam of light out of the side of the telescope barrel rather than through the other end. This allowed the telescope to be rotated at whatever angle without having to constantly move the eye piece. Most modern telescopes today use this configuration.
After two decades of moon gazing, Nasmyth co-authored the book The Moon Considered as a Planet, a World, and a Satellite with astronomer James Carpenter, where the duo put forward various hypothesis of the moon’s origin, its internal structure and geology. Nasmyth, like many astronomers of the day, believed that the craters on the moon’s surface were of volcanic origin. The book comes with many diagrams of cross-section of the celestial body’s subterranean layers to illustrate this idea, even drawing examples from the terrestrial world to demonstrate.
For instance, Nasmyth argued that as the lunar sphere cooled the outer layer solidified first and contracted, while the inner layers, still molten, expanded which Nasmyth calls “pre-solidifying expansion”. The expanding inner core strained against the contracting outer layers resulting in cracks from appearing on the lunar surface through which molten lava erupted forming the moon’s many craters. Finally, as the core cooled and shrunk it caused mountains to materialize just as shrinking muscles due to old age create wrinkles on the back of a hand. Nasmyth also demonstrated that the expanding interior caused the characteristic radiating streaks found on the moon’s surface by showing a photograph of a glass sphere cracked radially by pressure from within.
Although the science is incorrect, the images that accompanied the book were astounding. Even though fake, the photographs were —as NASA noted— “more realistic than the images that could be achieved by telescope photography at that time.” Ironically, a century later when the Apollo missions beamed home actual images and footage of the moon’s surface, the NASA and the government were accused of faking it all up—a ridiculous notion that refuses to die to this day.
In recognition of their work, both James Nasmyth and James Carpenter were honored with craters named after them.
For those interested in the book, a digital version is available for reading at archive.org.
[h/t Public Doman Review]
