Ramsay grease is a vacuum grease, used as a lubrication and a sealant of ground glass joints and cocks on laboratory glassware, e.g. burettes.
The soft grade is for large stopcocks and ground joints, desiccators, and for lower temperature use.
Ramsay grease consists of paraffin wax, petroleum jelly, and crude natural rubber, in ratio 1:3:7 to 1:8:16.
[5] The dropping point of Leybold-brand Ramsay grease is 56 °C; its maximum service temperature is 25-30 °C.
[6] An equivalent of Ramsay grease can be made by cooking lanolin with natural rubber extracted from golf balls.