We have to refer to the letter in your June issue from Mr. G. J. Vineall, Technical Director of Rocol Limited, the inaccuracy of which surprises us. Mr. Vineall stated that “if the oil is clear and pale it does not contain this solid additive”—i.e. molybdenum disulphide.
If sufficient care is taken to eliminate the larger particles of molybdenum disulphide by elutriation or other means a colloidal suspension can be made in which the molybdenum disulphide is not visible to the naked eye. It can, however, be detected under a reasonably powerful microscope, and can be suspended in large enough quantities to provide the full efficiency of molybdenum disulphide lubrication. These facts can be demonstrated.
We would point out that the two main advantages of the very small particle size required to give an apparently clear oil are the facts that molybdenum disulphide does not settle and that there is no possibility of clogging of filters or oil ways.
I am yours. etc.,
R. N. Gunn,
Director, Senol Limited.