Novembers Automotive column Synthetics: Origin of the Species certainly was most interesting. However, Steve Swedberg states that The first synthetic automotive oil was introduced by Superior, Wis.- based Amsoil in 1972.

I do not think that was an accurate statement, as the U.S. Army had developed and fielded a synthetic engine oil for both diesel and gasoline fueled vehicles/equipment and for power transmission fluid applications much earlier in 1967. This engine oil initially was introduced as Aberdeen Proving Ground Purchase Description Number 1 (APG PD #No. 1) titled Lubricating Oil, Internal Combustion Engine, Arctic, and was distributed for use in Alaska. This document was then shortly converted into the military specification MIL-L-46167, with the same title of APGD PD #NO. 1. This specification was quickly adopted by the commercial operators who began to build the Alaskan pipeline in the early 1970s.

Interestingly, APG PD #No. 1 contained a list of recommended suppliers that used three different types of base stocks in formulating this engine oil: a diester, a polyalphaolefin and a polyalkyl benzene. In a way, the APG PD No. 1 offered the user a selection of three different formulated engine oils to choose from.

Maurice E. Le Pera

Le Pera and Associates

Harrisonburg, VA 22801

An Image Problem

Dear LubesnGreases,

While everything Steve Swedberg wrote in his article Volatility: The Inside Story is fine (December issue, page 26), I thought it meaningless to include a photograph of the Selby-Noack apparatus on page 30. It serves no purpose other than perhaps an implied endorsement of the instrument.

In fairness, perhaps other instrument vendors models should have been shown as well. As it is, the Selby-Noack apparatus is used much less frequently than other instruments for this analysis. While it is part of the ASTM D5800 standard and gives equivalent results, this Procedure C is used by very few laboratories in the ASTM Proficiency Testing Programs (PTP). For example, in the most recent lube oil PTP sample, Procedure A was used by 14 participating laboratories, Procedure B by 38 and Procedure C by nine laboratories. Thus, there is no reason to give prominence to the Selby-Noack instrument other than as an advertisement.

I want to emphasize that I have no relationship whatsoever with any of the multiple Noack analyzer vendors.

Kishore Nadkarni

E. Brunswick, N.J.

Editors Response

Dr. Nadkarni, who is chairman of ASTM D02 Subcomittee 6 Noack Volatility Tests Task Force, is correct that more than one instrument may be used for testing Noack volatility. In discussing how to illustrate the article, LubesnGreases editors felt that it was useful to show what such a device might look like. The choice of image was not intended as an endorsement of this or any another product.