The celebration of an individual human birthday is an almost completely one-sided recapitulation of pleasant experiences in earlier years, together with a warmly optimistic forecast for coming years. This is wholly right and proper, although even here an occasional muted warning is of genuine value.

The celebration of a “technological birthday”, the review of the partial success, through one or more years of operation, of a man-sustained project, deserves notice of the same general type of review, promising further success, warning of potential difficulty, hoping for circumstances and facilities favourable to continued satisfaction, continuously qualified by mention of possible—indeed probable— change in the social climate, for good or ill.