, l~he m~t,hod s prev iously used fo r dete rminat,ion of the ignition temperatures of liqllid s~ a l e, blleft y l evl ewed, and the la rge dlscrepanc lCs 111 repo rted values no ted, Var iou s factors ~vh~ch affect the determmed values of ign it ion te mperature are d iscu ssed. A p ract ical IgmtlOn appa ratll s cons l~t ll1 g , In ]Jart of an , in sulated spherical flask, des ig ned to prov id e cOlldltlOns favorab le to low Ignition tempe rat ure values, IS desc ribed, and data obtai ned With thiS apparatus on a co nsiderable number of combustible liquids a re presented. The usefulness of , t une-temperature cu r ves of a t.hermoco uple junction p laced in mix t ures of ?ombu" tIble liqu id a nd a ll', as a means of studying the p reignit ion reactions in s Ll ch mixt ures IS Ill ustrated .