Calamities are of two kinds: misfortunes to ourselves, and good fortune to others.

—AMBROSE BIERCE

Watson did not conclude that Pauling’s DNA model was wrong just because it had three strands. Pauling’s nucleic acid molecule was simply not an acid at all. That is, it could not release positively charged hydrogen atoms when dissolved in water, the very definition of an acid. Instead, the hydrogen atoms were bound firmly to the phosphate groups, rendering those electrically neutral, while every elementary chemistry book (including Pauling’s own book!) stated that the phosphates had to be charged negatively (the acid is highly ionized in aqueous solution). There was no way to extract those hydrogen atoms, either, since they were actually the key links holding together the three strands through hydrogen bonds.

This blunder was just too much for Watson and Crick to swallow. The world’s greatest chemist constructed a completely defective model, and the model was wrong not because of some subtle biological feature but because of a major blooper in the most basic chemistry. Still incredulous, Watson rushed to Cambridge chemist Roy Markham and to the organic chemistry laboratory to check with them whether there was any doubt that DNA, as it occurs in nature, was indeed the salt of an acid. To Watson’s satisfaction, they all confirmed the unthinkable: Pauling had utterly botched the chemistry.

There were only two things left to do that day. First, Crick hurried to Perutz and Kendrew to convince them that urgency was of the utmost importance. Unless he and Watson got busy with modeling immediately, he argued, it wouldn’t be long before Pauling discovered his mistake and revised his model. Crick estimated that they had no more than about six weeks to come up with a correct model. Watson and Crick’s second action was equally obvious to the two young men: They went to celebrate at the Eagle Pub on Bene’t Street. Watson later recalled, “As the stimulation of the last several hours had made further work that day impossible, Francis and I went over to the Eagle. The moment its doors opened for the evening we were there to drink a toast to the Pauling failure.”