The crystal. The crystal of an atmosphere: Name of Machines. Maximum. Minimum. Holmes 1,523 1,523 Alliance 1,953 1,953 Gramme (No. 2). 6,663 4,016 Siemens (Large) 14,818 8,932 Siemens (Small, No. 1) 5,539 3,339 Siemens (Small, No. 2) 6,864 4,138 Two.