In the1975 Yearbook of Jehovah's Witnesses on Page 121, it says:
http://blogs.ebay.com.au/professortextbook/entry/Jehovah-Chose-the-Jehovahs-Witnesses-by-Giving-Th/_W0QQidZ50095019Upon Brother Rutherford’s return to the Society’s Pittsburgh offices, he instructed the Society’s vice-president, C. A. Wise, to go to Brooklyn and see about reopening Bethel and renting premises where the Society could begin printing operations. The conversation went like this:
"Go and see whether it is the Lord’s will for us to return back to Brooklyn."
"How will I determine as to whether it is the Lord’s will for us to go back or not?"
"It was a failure to get coal supplies in 1918 that drove us from Brooklyn back to Pittsburgh. Let’s make coal the test. You go and order some coal." [In New York coal was still being rationed at the end of the war.]
"How many tons do you think I should order to make the test?"
"Well, make it a good test; order five hundred tons."
That is just what Brother Wise did. And upon making application to the authorities, he was granted a certificate to get five hundred tons of coal. Immediately he wired J. F. Rutherford. That much coal would ensure operations for a number of years. But where could they put it all? Large sections of the Bethel home’s basement were converted into coal storage space. This successful test was taken as an unmistakable indication that it was God’s will that the move to Brooklyn be made. So it was, as of October 1, 1919.