Zoetrope: An 1834 Paper Said a Whole Room Could Watch It

Count the slits on this Auckland Museum drum, multiply by its turns per second, and you get pictures per second. That one line of arithmetic is how a zoetrope works. A strip of drawings sits inside the drum, and each slit gives you a short look at one drawing, in the same spot as the drawing before it. On a drum with 12 slits and one turn a second, you see 12 images a second: a new one about every 83 milliseconds.

The museum dates this drum only to the 19th century, but the form itself was in print by 1834. In 1834 W. G. Horner described “a hollow cylinder” with “apertures at equal distances” in the Philosophical Magazine, and he gave it a name of his own: the Dædaleum.

How does a zoetrope work?

Open the diagram full size

Hold the drum at eye level and look through one slit, and your line of sight skips the near wall entirely, crossing the empty middle to the far wall, where the strip sits. Horner put it plainly: drawings made on the inside, between the openings, “will be visible through the opposite apertures.”

Lutz’s 1920 handbook, Animated Cartoons, describes the toy. It was “like a cylindrical lidless box of cardboard,” balanced on a vertical rod so that, he says, it could turn very fast. The slots ran around the upper rim, and long paper strips of drawings fitted inside.

Now spin it. The wall between two slits blocks your view, and the next slit opens it again a moment later. Lutz lists this among four elementary features of nearly all the apparatus built while the art was developing: “Some means by which light—or the vision—is shut off while the change from one picture to another is taking place.” In a zoetrope the solid strips of wall do that job, while the slits only control when you get to look.

Go back to the Auckland drum with that in mind. Flecks of color show through two of its slits. Those flecks sit inside the drum, on the far side, because a slit is a window across the drum, not into the near wall.

Two neighbors are easy to mix up with it. The phenakistiscope is a flat disk with slits, spun in front of a mirror. The praxinoscope keeps the drum but, in Lutz’s words, “made use of the reflective property of a mirror”: a ring of mirrors set halfway between the center and the wall. An open drum with slits and no mirrors is a zoetrope.

Slits times turns: how many pictures a second?

Every number in the table below comes from one multiplication. The slit count is fixed by the drum, and the turning speed is up to the hand that spins it. Neither Horner nor Lutz gives a speed, so the speeds here are assumptions, not measurements.

The loop below runs the middle row. It is a model drum, not a real strip: 12 drawings of a dot, each placed 30 degrees further around a circle, shown for two full turns. One turn shows all 12 drawings once, so the two-second loop holds each drawing twice. Between frames the dot moves the same distance every time, including from the last drawing back to the first.

A 12-slit drum at one turn per second, two turns

Every frame, side by side

1. 1drawing 1, turn 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 7
8. 8
9. 9
10. 10
11. 11
12. 12
13. 13drawing 1, turn 2
14. 14
15. 15
16. 16
17. 17
18. 18
19. 19
20. 20
21. 21
22. 22
23. 23
24. 24

At 6 images a second the same 12 drawings take two seconds to go round, and the steps start to show. Spacing works the same way when the drawings change instead of the speed, which is the whole subject of bouncing ball animation: closer drawings read as slow, wider gaps read as fast.

Download the zoetrope names and timing table (CSV) · source and license notes

Why did Horner say a whole room could watch?

Horner opened his paper by crediting “the ingenious and amusing invention of M. Plateau,” the slotted disk you spin in front of a mirror. That disk is the phenakistiscope, which you hold close to your face, watching the drawings in the glass.

The open drum dropped the mirror. Horner wrote that it could be performed “without a mirror or any second instrument,” and that there was no need “for bringing the eye near the apparatus.” Because of that, he said, it could be shown “to unlimited numbers at once” and “with full effect to a numerous audience.” Those are Horner’s claims about his design; his paper does not record a showing, so this page treats the whole-room point as what Horner said the drum allowed, not as a crowd anyone counted.

The drum belongs with the other parlor optics that build something from flat pictures. The stereograph makes depth from two photographs; the zoetrope makes motion from a strip of drawings.

Who invented the zoetrope?

Three dates sit on the record, and each stands for a different kind of claim.

Lutz wrote that the toy, “as a matter of priority, is associated with the name of Desvignes”. He spells the general device zootrope, also calls it the wheel of life, and does not mention Horner in these pages. He adds that the drum “was sold as a toy for many years,” with paper bands of comic and entertaining subjects made to fit it.

Horner, for his part, credited Plateau for the disk and Faraday and Roget for the principles behind it. Neither patent was read for this page; the 1860 and 1867 dates are Lutz’s.

In a later chapter Lutz hedges his own priority line. There he credits Desvignes with inventing one form of the zootrope. He also records that Desvignes made a series for it as far back as 1860, showing a steam engine at work. One form among several is a fair way to read the whole record.

So the honest answer is a range, 1834 to 1867, with three claims side by side: a published description and name, an English patent, and a US patent for a device its owner called the zoetrope. A single inventor and a single year would claim more than these pages show. The museum record for the strip below also dates it to about 1860, years before the US patent.

Reading a strip: twelve couples, one turn

Count the couples on the Cooper Hewitt strip and you get 12 (this site’s count). Spread over 84.3 cm, that puts a drawing about every 7 cm (84.3 ÷ 12 = 7.025), assuming even spacing along the whole length.

In drawing 1 the man’s back is toward you, by drawing 7 the woman’s back has come round, and by drawing 12 the man’s back is turning toward you again, so drawing 1 can follow drawing 12 with no break.

The loop below cuts the strip into those 12 drawings and plays them at 6 a second. That is the slow row of the table: 12 slits at an assumed half turn per second, so one turn of the dance takes two seconds.

Dancers strip, one turn at 6 images a second

Every frame, side by side

1. 1drawing 1, start of the turn
2. 2
3. 3
4. 4
5. 5
6. 6
7. 7
8. 8
9. 9
10. 10
11. 11
12. 12drawing 12, then back to 1

The drawings were designed as a cycle, so the last one hands back to the first. The twelve frames of The Horse in Motion were photographed instead of drawn, and their loop has to come from the horse’s own stride.