--- description: In Boston one day last week officials of Provident Institution for Savings watched the 30-ton door of their bank vault ponderously close and lock. A motor compressor forced air into the vault through... title: Science: Watertight image: https://static.time.com/v3/assets/bltea6093859af6183b/bltde093bcdab65f2d0/6988d9b9bc6cfc69913e2a3c/time-logo.jpg?branch=production --- * [U.S.](/section/us/) # Science: Watertight by [TIME](/author/time/) Dec 3, 1934 5:00 AM CUT by [TIME](/author/time/) Dec 3, 1934 5:00 AM CUT In Boston one day last week officials of Provident Institution for Savings watched the 30-ton door of their bank vault ponderously close and lock. A motor compressor forced air into the vault through a ventilator until a pressure-gauge climbed to 4 Ib. per square inch over atmospheric pressure. At that level the gauge stood still nearly an hour after the air input had stopped. A valve was then opened and the compressed air wheezed out. First of its kind that anyone knew of, the test showed the vault airtight, hence watertight. With safety-deposit boxes only six inches from the floor, the bank’s officials deemed the possibility of a flooded basement real enough to be guarded against. The door was built by York Safe & Lock Co., machined by hand to such precision that a scrap of tissue paper in the frame prevents it from closing. Science: Watertight ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/archive/6863271/science-watertight/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/archive/6863271/science-watertight/"},"headline":"Science: Watertight","datePublished":"1934-12-03T05:00:00.000Z","dateModified":"2026-03-13T18:30:15.427Z","description":"In Boston one day last week officials of Provident Institution for Savings watched the 30-ton door of their bank vault ponderously close and lock. A motor compressor forced air into the vault through...","url":"https://time.com/archive/6863271/science-watertight/","keywords":[],"thumbnailUrl":"","author":[{"@type":"Person","name":"TIME","url":"https://time.com/author/time/"}],"articleSection":"U.S.","image":[],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/us/","name":"U.S."}},{"@type":"ListItem","position":2,"item":{"@id":"https://time.com/archive/6863271/science-watertight/","name":"Science: Watertight"}}]}] ```