Hannan & Buchanan (Firm)

• Buchanan's improved patent Delta metal pressure, vacuum, and compound gauges (Bourdon's patent)
• Buchanan's patent improved Bourdon gauges
• Buchanan's patent improved Richard's steam engine indicator
• Buchanan's patent steam engine indicator
• Richard's improved patent steam-engine indicator
• Special quality of metallic paper for Buchanan's patent and Richard's indicator