In the August 12, 1905, issue of The Academy, a popular London literary

Magazine, a correspondent gave the criteria by which he felt a pi mnemonic should be judged:

They are easy to construct, but the problem is how to obtain a mnemonic which shall contain as complete a reference as possible to the point in question: (1) That pi is the ratio of the circle to its diameter, (2) that the series is infinite, and (3) that the words translated into the number of their letters, give the value of pi.

I would give different criteria: (1) that they should say something entertaining or worth knowing and (2) that the mnemonic should rhyme. These two criteria are hard to satisfy.

3.14159 26535 89793 23846 26433 83279 (inspired by Lucas) Let 7r mean a ratio (circulars to 'meters) Whose end beats straight computers, staunch computers, And, to ten decimals plus twenty, pi arises From our pet verselet all in numeral disguises.

—W. Renton, The Academy, vol. 69, no. 1735 (August 12, 1905), page 796. [Note the use of both "7r"and "pi".]

3.14159 26535 89793 23846 26433 83279 Now I will a rhyme construct, By chosen words the young instruct, Cunningly devised endeavors, Con it and remember ever Widths in circle here you see Sketched out in strange obscurity—.

—Author unknown, The Dark Horse, the staff magazine of Lloyd's Bank (1951). [con = to learn or commit to memory]

3.14159 26535 89793 23846 26433 83279 5 Sir: I wish I could recapture my memory about Sir Jeans' diabolic mnemonics! However, invention now of any reliable easy phrase is beyond what shy and fumbling aid my present intellect gives.

—Bill Powers (Chicago), in Willey Ley, The Borders of Mathematics (Pyramid Publications, 1967), page 149.

3.14159 26535 89793 23846 26433 83279 5 May I have a month, professor, To figure these, you brain assessor? Calculate, student, calculate now! As the figuring gets longer, My friend, hope you get stronger And no figures, incorrect, allow.

—Aaron L. Buchman, School Science and Mathematics, vol. 53 (February 1953), page 106.

3.14159 26535 89793 23846 26433 83279 5 You I sing, O ratio undefined By strict assay and lined, Sequence limitless. Stunned regarding you, We see eternity—alas~nwind In random cast and rue, Dejected out of measure, reckoning blind.

—John Freund (English Department, Grand Valley State College, Allendale, Michigan), The Mathematics Teacher, vol. 62 (April 1969), page 348.

3.14159 26535 89793 23846 26433 83279 5 May I tell a story purposing to render clear the ratio circular perimeter-breaths, revealing one of the problems most famous in modern days, and the greatest man of science anciently known.

—C. J. Jackson, Mathematical Gazette, vol. 4 (July 1907), page 103.

One of the longest mnemonics ever written for pi was published in the Journal of Recreational Mathematics (vol. 8, no. 3, 1975 - 1976, page 226) by Michael Keith of Hazlet, New Jersey. The mnemonic is a 216-word story of a fictional exploration of Mars, entitled "To Explore A Memorial to Martians." It begins as follows:

For a time I tried exploring in gloomy shade. The thick darkness descended quickly. Tenseness lay in the twilight.

The story ends with "The End," as the 215th and 216th digits of pi are both 3. The author used the convention of letting every punctuation mark (other dhan a period) stand for zero. In certain places, single words of 10, 11 or 12 letters are used to express two digits: 1, 0 or 1, 1 or 1, 2. Curiously, dhe tide is a six-digit mnemonic for e.