Figure 6. These graphs are the same as Figure 5, but for HC as propane.

Politics and business have been important in the development of this system. The business dealings have been both complex and confusing. I am often asked, "Why is your instrument owned by Envirotest?" The slightly flippant answer is, "If you saw a product that could put your main product line out of business, wouldn't you want to own it?" One day I hope to convince them that they can make more profit per dollar invested by selling twenty-five cent tests at 1000 per hour, than twenty-five dollar tests at 10 per hour. A more complex answer goes into the details of how we got where we are.

The steps by which the DU technology became owned by Envirotest were quite complex. The original license agreement was with a consortium: Sun Electric in Chicago, which makes garage analyzers for exhaust gases, and Systems Control of Sunnyvale, Calif., which carries out centralized testing. These two corporations already had formed a consortium, namely Vehicle Testing Technology Inc. (VTTI), which ran the emission testing program in Seattle. Within a few years, Systems Control was sold to ETC and in turn to Hamilton Test/Enviro-test, and Sun Electric was sold to Snap-On Tools. This could have been a stable situation, but VTTI was left 100% with