Update: I found some more fascinating info on the time capsules. Interesting read.
Items enclosed in the 1964 Time Capsule II. One group of items was titled Articles in Common Use. #4 was listed as:
"Electronic watch: employing principle of natural vibration to tell time electrically. Provided by Bulova Watch Company."
Wikipedia has a great entry under - Westinghouse Time Capsules.
Akkatron, regarding your comment above about having a box that's resistant, check out the description below of the material used for both the 1939 and 1964 Capsules.
"Time Capsule I was made of a non-ferrous alloy called Cupaloy, created especially for this project. Designed to resist corrosion for 5,000 years, the alloy was made of 99.4% copper, 0.5% chromium, and 0.1% silver. Westinghouse claims it has the same strength as steel, yet will resist most corrosion over thousands of years like copper, because it becomes an anode in electrolytic reactions, receiving deposits instead of wasting away like most iron-bearing metals. Time Capsule II was made of a stainless steel metal called "Kromarc", supplied by U.S. Steel. Westinghouse Research Laboratories determined with extensive chemical testing that this new super stainless steel alloy would resist corrosion much like the alloy that was used for Time Capsule I. Invented by Frederick Charles Hull, Kromarc 55 Stainless Steel is composed of 52.60% iron, 21.24% nickel, 15.43% chromium, 8.20% manganese, 2.15% molybdenum, 0.22% silicon, 0.05% carbon, 0.013% phosphorus, and 0.012% sulfur."
The contents were then sealed inside inner glass envelopes with either nitrogen or argon gas.