According to the Guinness Book of Records, the MAG*I*CAL calibration sample for TEM is officially the

"WORLD'S SMALLEST RULER"

The MAG*I*CAL sample was first honored with a listing as "The World's Smallest Ruler" in 1998, and has not been successfully challenged since. The 1998 Guinness Book entry reads:
Smallest Ruler
In 1994 a ruler used for measuring lengths in an electron microscope was developed by John McCaffrey and Jean-Marc Baribeau, two Canadian physicists. The ruler's smallest division is 18 atoms thick and five of the rulers stacked end to end would equal the diameter of a human hair.

However, there was an error in the citation! In fact, TEN of the MAG*I*CAL's stacked end to end would equal the thickness of a human hair. The Guinness Book of Records graciously corrected this error in the 2002 version of the Book.

The prestigious journal Science also carried news of the recognition of the MAG*I*CAL's recognition as the World's smallest Ruler. On February 7, 1997, the following note was published:

Science Vol. 275, Number 5301, February 07, 1997, pp. 761-0.



John McCaffrey (L) and Jean-Marc Baribeau (R) contemplate the grave responsibility which comes with an entry in the Guinness Book of Records.

MAG*I*CAL is a Registered Trademark of Norrox Scientific Ltd.