I didn't know Michael Heizer until I was preparing for my "Earthworks" show in 1968, and somebody called and told me to look at his work. Heizer had already made land art before any of the others and was deeply into it. But he was very young and working out West, so I wasn't aware of his work until he came and showed it to me.

The gallery closed its doors in 1971. I could no longer psychologically handle the needs of 12 artists. I cared about all of them, and what was happening with their careers. I'm just not a person who can do that indefinitely. And tax-wise I was concerned because they gallery wasn't making money; it was losing money.

Had opened a gallery I already had strong connections with New York, because I was taking work on consignment from New York dealers. So I already knew a great many of the dealers and the artists here. It wasn't cold for me.

Art wasn't for selling. Actually, we once did have an offer on Double Negative. Things could be sold actually - everything could be for sale. But we had very few buyers. I think it was Michael Heizer who said that the point was to have a bigger canvas, and I've used that expression quite a bit. But I was thinking today that a canvas has boundaries; it has limit to it. And for earthwork, it was the very openness and feeling that there were no boundaries that made it so exciting.

What's happening in the larger world always influences art. When I first started the gallery in 1959, one of the first things I learned was that most people assume artists know one thing and one thing only - that they were idiot savants. I found very quickly that most artists were very informed and very aware of what was happening in the world around them. So all of those things go together, especially for earthworks. And at that time there was such an intense interest in American art. So there was a great deal of attention paid to where it was going.

People should go to the works and experience them. Because just having an idea or picture in mind is absolutely not the experience that's necessary. Even just landing in Albuquerque or Salt Lake City or Las Vegas was immediately part of the experience. And then you'd get in a car from the airport and take these very long trips - in Michael Heizer's case, it was three hours by car to get to his work. And then there's walking around and into the piece and seeing it from different angles. The kinetic experience of being a part of it physically was very important for me.

I enjoyed cross-country road trips. And I found the work challenging because it was art that existed on the land rather than mere concepts in a gallery or photographic documentation, or any of the paraphernalia that can be used to indicate that. The art was on the land.