##
Mathematical Paintings of Crockett JohnsonAbout

CJ, as he signed himself, first became known to the general public through the cartoon strip Barnaby which ran in the 1940s and again in the early 1960s. It featured five-year-old Barnaby Baxter, his family, and Mr. O’Malley, his cigar-smoking “fairy godfather.” Their adventures appeared in a few dozen newspapers and were collected in paperback books. Crockett Johnson also illustrated and wrote children’s books, most notably *Harold and the Purple Crayon*.

Crockett Johnson was not alone in finding mathematics an inspiration for art. Contemporary painters such as Piet Mondrian, Ad Reinhardt, Josef Albers, Alexander Calder, and Richard Anuszkiewicz used geometric forms in their paintings. Artists like Alfred Jensen paid tribute to mathematicians in paintings like *Honor Pythagoras – Per I – Per IV* (1964).

Crockett Johnson was unusual in that he linked geometric constructions and specific mathematicians. As he explained to artist friend Ad Reinhardt in 1965, he planned “a series of romantic tributes to the great geometric mathematicians from Pythagoras on up; in other words the shapes and disciplines are pilfered (but interpretation is the greatest form of plagiarism and besides I am very willing to share credit with Euclid, Descartes, et al).”

He based his early paintings on diagrams in a volume compiled by James R. Newman entitled *The World of Mathematics* (1956). As time went on, he took a more active interest in following the mathematical arguments in books, and then began to develop his own geometric constructions. This led him to two mathematical publications, one on estimating geometrically the value of the number pi and another on constructing a polygon with seven equal sides.

Crockett Johnson did not attempt to master all the technical details of painting. He preferred to do small paintings, to paint on masonite rather than canvas, and to use house paint mixed at a local hardware store. His paintings were shown at the Glezer Gallery in New York City, at the IBM Gallery in Yorktown Heights, New York, at the General Electric Gallery in Fairfield, Connecticut, and at what is now the National Museum of American History. Many of the works adorned the walls of his home in Connecticut and were treasured by him and by his wife, the author Ruth Krauss. One painting was donated to the Museum in1975, the others were given in 1979. In recent years, the paintings and Crockett Johnson’s work in general have received attention from several scholars.

"Mathematical Paintings of Crockett Johnson - About" showing 3 items.

## Painting -

*Homothetic Triangles (Hippocrates of Chios)*- Description
- Two polygons are said to be homothetic if they are similar and their corresponding sides are parallel. If two polygons are homothetic, then the lines joining their corresponding vertices meet at a point.

- The diagram on which this painting is based is intended to illustrate the homothetic nature of two polygons ABCDE . . . and A'B'C'D'E' . . . From the title, it appears that Crockett Johnson wished to call attention of homothetic triangular pairs ABS and A'B'S, BCS and B'C'S, CDS and C'D'S, DES and D'E'S, etc. The painting follows a diagram that appears in Nathan A. Court's
*College Geometry*(1964 printing). Court's diagram suggests how one constructs a polygon homothetic to a given polygon. Hippocrates of Chios, the foremost mathematician of the fifth century BC, knew of similarity properties, but there is no evidence that he dealt with the concept of homothecy.

- To illustrate his figure, the artist chose four colors; red, yellow, teal, and purple. He used one tint and one shade of each of these four colors. The larger polygon is painted in tints while the smaller polygon is painted in shades. The progression of the colors follows the order of the color wheel, and the black background enhances the vibrancy of the painting.

*Homothetic Triangles*, painting #17 in the Crockett Johnson series, is painted in oil on masonite. The work was completed in 1966 and is signed: CJ66. It is inscribed on the back: Crockett Johnson 1966 (/) HOMOTHETIC TRIANGLES (/) (HIPPOCRATES OF CHIOS). It has a black wooden frame.

- References: Court, Nathan A.,
*College Geometry*, (1964 printing), 38-9.

- van der Waarden, B. L.,
*Science Awakening*(1954 printing), 131-136.

- Location
- Currently not on view

- date made
- 1966

- referenced
- Hippocrates of Chios

- painter
- Johnson, Crockett

- ID Number
- 1979.1093.11

- catalog number
- 1979.1093.11

- accession number
- 1979.1093

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Painting -

*Squared Lunes (Hippocrates Of Chios)*- Description
- Classical Greek mathematicians were able to square all convex polygons. That is, given any polygon, they could produce a square of equal area in a finite number of steps using only a compass and a straight edge. Figures with curved sides proved more difficult. However, as this painting suggests, the mathematician Hippocrates of Chios (5th century BC) squared a lune, a figure bounded by arcs of two circle with different radii (lunes resemble quarter moons, hence the name). Finding the area of a lune in terms of a square might seem more difficult than squaring a circle, but the latter problem would prove intractable.

- The painting follows annotated figures in Evans G. Valens's
*The Number of Things*(1964), p.103, which was part of Crockett Johnson's mathematical library. It corresponds to an early diagram in Valens's discussion of squaring the circle. According to Valens, Hippocrates began by arguing that the areas of similar segments of different circles are in the same ratio as the squares of their bases. Suppose an isosceles right triangle is inscribed in a semicircle of diameter c. Construct smaller semicircles of diameter a and b on the sides of the inscribed triangle. As the square of a plus the square of b equals the square of c, the area of the two smaller semicircles equals that of the large one. The proof goes on to consider the area of the two crescents and the triangle.

- In this version of
*Squared Lunes*Crockett Johnson uses brown, black, red, and white against a gray background. This oil painting is #67 in the series, and the first in the series with the title "Squared Lunes." It was completed in 1968 and is signed: CJ68. It is inscribed on the back: SQUARED LUNES (/) (HIIPPOCRATES OF CHIOS) (/) Crockett Johnson 1968. A related painting is #68 (1979.1093.43).

- Location
- Currently not on view

- date made
- 1968

- referenced
- Hippocrates of Chios

- painter
- Johnson, Crockett

- ID Number
- 1979.1093.42

- accession number
- 1979.1093

- catalog number
- 1979.1093.42

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Painting -

*Squared Lunes (Hippocrates Of Chios)*- Description
- The title of this painting refers to Hippocrates of Chios (5th century BC), one of the greatest geometers of antiquity. Classical Greek mathematicians were able to square convex polygons. That is, given a polygon, they could produce a square of equal area in a finite number of steps using only a compass and a straightedge. They were unable to square a circle. This painting is based on the earliest known squaring of a figure bounded by curves rather than straight lines. The mathematician Hippocrates squared a lune, a figure bounded by arcs of two circles with different radii. This achievement might seem more difficult than squaring a circle.

- Crockett Johnson's painting follows two annotated figures in Evans G. Valens's
*The Number of Things*(1964), pp. 103–104, a book in the artist’s mathematical library. The finished piece shows isosceles triangles T, and a second congruent triangle connected to it base to base to form a square. Also present in the painting are three lunes, two small and one large. The area of triangle T is equal to the sum of the areas of lunes A and B (see figures). The area of triangle T is also equal to the area of a lune composed of X, Y, and the area T-C. Furthermore, because triangle T is congruent to the triangle below it, triangle T is equal to the area of this lune. Thus, the area of the square is equal to the sum of the areas of the three lunes. In summary, Johnson pictorially represented a "squared" curvilinear region; that is, he successfully constructed a square with the same area as that of the region of three lunes bounded by curves.

- Crockett Johnson executed this painting in 4 tints and darker shades of purple upon a black background. The center triangle is the darkest shade of purple. As one moves outward, the colors grow lighter. This allows a dramatic distinction to be seen between the figure and the background, and thus puts a greater emphasis on the lunes.

- This oil painting on masonite is #68 in Crockett Johnson's series. Its date of completion is unknown and the work is unsigned. It is closely related to painting #67 (1979.1093.42).

- Location
- Currently not on view

- date made
- ca 1965

- referenced
- Hippocrates of Chios

- painter
- Johnson, Crockett

- ID Number
- 1979.1093.43

- accession number
- 1979.1093

- catalog number
- 1979.1093.43

- Data Source
- National Museum of American History, Kenneth E. Behring Center