The fixtures, tools, machinery, and apparatus which are necessary to carry on a trade or business. Wharton. Southern Bell Tel. Co. v. D’Alemberte, 39 Fla. 25, 21 South. 570; Sloss-Sheffield Steel Co. v. Mobley, 139 Ala. 425, 30 South. 181; Maxwell v. Wilmington Dental Mfg. Co. (C. C.) 77 Fed. 941.