All necessary preliminary expenses actually incurred by the board of any municipality or municipalities in the making of surveys or estimates of cost and of revenues, employment of engineers or other employees, the giving of notices, the taking of options, and all other expenses of whatsoever nature necessary to be paid prior to the issue, sale and delivery of the revenue bonds herein provided for, may be paid by the municipality or municipalities, to be reimbursed and repaid out of the proceeds of the sale of such revenue bonds to be used for the construction, reconstruction, establishment, acquisition, improvement, renovation, extension, enlargement, increase, equipment or repair (including replacements) of such works as hereinafter provided.
