Murray Leinster 
The Runaway Skyscraper [EPUB ebook] 

The whole thing started when the clock on the Metropolitan Tower began to run backward. It was not a graceful proceeding. The hands had been moving onward in their customary deliberate fashion, slowly and thoughtfully, but suddenly the people in the offices near the clock’s face heard an ominous creaking and groaning. There was a slight, hardly discernible shiver through the tower, and then something gave with a crash. The big hands on the clock began to move backward.
Immediately after the crash all the creaking and groaning ceased, and instead, the usual quiet again hung over everything. One or two of the occupants of the upper offices put their heads out into the halls, but the elevators were running as usual, the lights were burning, and all seemed calm and peaceful. The clerks and stenographers went back to their ledgers and typewriters, the business callers returned to the discussion of their errands, and the ordinary course of business was resumed.
Arthur Chamberlain was dictating a letter to Estelle Woodward, his sole stenographer. When the crash came he paused, listened, and then resumed his task.
It was not a difficult one. Talking to Estelle Woodward was at no time an onerous duty, but it must be admitted that Arthur Chamberlain found it difficult to keep his conversation strictly upon his business.
He was at this time engaged in dictating a letter to his principal creditors, the Gary & Milton Company, explaining that their demand for the immediate payment of the installment then due upon his office furniture was untimely and unjust. A young and budding engineer in New York never has too much money, and when he is young as Arthur Chamberlain was, and as fond of pleasant company, and not too fond of economizing, he is liable to find all demands for payment untimely and he usually considers them unjust as well. Arthur finished dictating the letter and sighed…