§ 22. When appropriations are available; appropriations for two or more objects. No item of an appropriation made for the performance of such work shall be available, except for advertising or expenses incurred in the preparation of plans and specifications, engineering work or superintendence, unless one or more contracts or special orders shall first have been made for the completion of such work within the appropriation therefor. If an appropriation be made for the construction, reconstruction, alteration, repair or improvement of any state buildings in an appropriation act specifying two or more objects for which the appropriation is made and any one of such objects shall have been accomplished for a sum less than the amount specified in the act, the unexpended balance shall be applicable to any other work specified in the act.