The Seaway Saga

What a great article by Daniel J. McConville (“Seaway to Nowhere,” Fall 1995). My husband and I marveled through the entire story, wondering why all that work hadn’t reached the consciousness of our family in the 1950s. Both of us thought the Seaway had been completed several decades earlier. We could scarcely believe that America had so shortchanged its cooperation with Canada. And the part on the problems encountered with the glacial till was dumbfounding. No wonder the author is now a journalist: Writing about such troubles must be easier than actually physically struggling through them daily.

Beatrice L. Burch
Kailua, Hawaii

The Seaway Saga

Having grown up along the St. Lawrence Seaway, I found the article on its development both enjoyable and enlightening.

One small point deserves comment however. The author advances the notion that crystallization was the root cause of failure in ferrous-metal parts of construction equipment in the cold winters. In the days prior to the development of X-ray diffraction, crystallization was invoked to explain many metallurgical failures, especially fatigue failures. However, since then metallurgists have learned that metals are inherently crystalline from the point of solidification, unless extraordinary measures are taken to very rapidly solidify them.

The true cause of failure of these ferrous structures was most likely the ductile-to-brittle transition common to body-centered cubic materials. The fact that metallurgists once explained such failures as induced by crystallization is understandable given the appearance of the fracture faces.

Richard G. Rateick, Jr.
South Bend, Ind.

Air Ray Attack?

Your Summer 1995 article “Postfix: Killer Air Ray,” by Alexander Roca, reminded me of an experience I had in World War II. While I was flying as a copilot of a B-17 bomber some 25,000 feet over Germany, my plane was tossed around by an unusual shock. We were in clear air, far from the prop wash of the group in front of my squadron. I had experienced clear-air turbulence and severe prop wash before, but this was like being hit from underneath with the same effect. We were almost tossed into the plane on our left.

I remember seeing an article in some magazine after the war that showed a picture of a scrapped German air gun. My airplane may have been the only one they ever hit—though the article “The Wind Gun” in Maj. Gen. Leslie E. Simon’s book Secret Weapons of the Third Reich says that their version “produced no appreciable effect on aircraft at normal ranges.”

George W. Intemann
Kiawah Island, S.C.

The Dentist’s Progress

In the spring of 1959 I went in for the routine annual physical that the Air Force required. During the dental exam I expected to hear that I had the usual no cavities, or at most one. To my surprise, the dentist announced that I had five. While he was drilling and filling them, I noticed that his drill had a very high-pitched whir and I was smelling hot tooth enamel. After he was done, I asked, “Did you get a new type of drill?” His reply came quickly: “We sure did, and it’s a dandy!” When I read “Behind the Dentist’s Drill,” by Malvin E. Ring (Fall 1995), I recognized the Airotor, with its angled head. That dentist sure had been eager to use his new toy!

John W. MacDonald
Stevensville, Mont.