I wrote down the following quotes from Watson's "The Double Helix" while seeking to better understand the role that physical models had upon the discovery of DNA. The following may contain mistakes; it's transcribed from a photograph of my pocket notebook, with notes written on Boston's Esplanade on April 14, 2001. The original photos can be viewed here.

--Brygg Ullmer, April 25, 2003

I found the following sentence among the most interesting (and in part, the most troubling). The following observation was apparently made immediately following the publication of Watson and Crick's 1953 Nature article reporting the structure of DNA:

p212: "Obviously affecting Rosy's transformation was her appreciation that our past hooting about Model building represented a serious approach to science, not the easy resort of slackers who wanted to avoid the hard work necessitated by an honest scientific career..."

[I find the beginning of this last sentence, and some of the sentences that preceed it, a bit troubling. Some relevant discussion about Rosalind Franklin appears here, among other places. ]

More quotes establishing the important role played by physical models in Watson and Crick's work:

p172: "After saying that I was going to ask a Cavendish machinist to make models of the purines and pyrinidines, I remained silent, waiting for Bragg's thoughts to congeal."

p173: "I then [raced?] down the stairs to the machine shop to warn there that I was about to draw up plans for models wanted within a week..."

p175: "No serious models were built, however, for several days... Since our machinist needed at least three days merely to turn out the more simple [phosphoro...] atoms..."

p178: "The next morning, however, as I took apart a particularly repulsive backbone-centered molecule..."

"... At this stage Francis' interest began to perk up, and at increasing frequencies he would look up from his calculations to glance at the model."

p194: "The metal... models ... had not been finished on time. I spent the rest of the afternoon cutting accurate representations of the bases out of cardboard."

p197: "However, we both knew that we would not be at home until a complete model was built in which all the stereochemical [contacts?] was satisfactory."

p200: "...whether the shop could be speeded up... Only a little [...] was needed to get the final soldering accomplished in the next couple hours..."

p201: "Only one person can easily play with a model, and so Francis did not try to check my work [...]. I backed away and said that I thought everything fitted. ... Thus, the next several days were to be spent using a plumb line and a measuring stick..."

p203: "He was already at work tightening the model on its support stands... ...kept me from observing he needed my help to keep the model from collapsing as he rearranged the supporting ring stands..."

p219: "He thus set about building a model with tilted bases..."