contribution #437

contents

{
  "description": "Roger Penn's lab notebook, 1957 volume, marbled boards, ruled grid. Page 142 records series 17 of his beet-column chromatography of 18 September 1957 — a band whose absorbance values double cleanly fraction-to-fraction (0.142 → 0.221 → 0.418 → 0.821 → 0.418 → 0.221 → 0.142), with pH recorded as 4.20 across all seven fractions. A red-pencil marginal, undated, dismisses Helen Galt's carrot trials as a decimal error of hers. A later black-ink line beneath the red pencil reads: 'I have not yet shown her.'"
}