Mr. ROWLAND. I don't know. A lot of people laughed. I don't know. But a lot of people laughed, chuckled, such as this. Then approximately 5 seconds, 5 or 6 seconds, the second report was heard, 2 seconds the third report. After the second report, I knew what it was, and---- Mr. SPECTER. What was it? Mr. ROWLAND. I knew that it was a gun firing. Mr. SPECTER. How did you know that? Mr. ROWLAND. I have been around guns quite a bit in my lifetime. Mr. SPECTER. Was the sound of the fire different from the first and second sounds you described? Mr. ROWLAND. No, that is just it. It did not sound as though there was any return fire in that sense. Mr. SPECTER. What do you mean by return fire? Mr. ROWLAND. That anyone fired back. You know, anyone in the procession such as our detectives or Secret Service men fired back at anything else. It gave the report of a rifle which most of the Secret Service men don't carry in a holster although I am sure they had some in the cars but the following two shots were the same report being of the same intensity. I state, because from a different position I know that the same rifle is not going to make the same sound in two different positions especially in a position such as it was, because of the ricocheting of sound and echo effects. Mr. SPECTER. What is your basis for saying that, Mr. Rowland, that the rifle would not make the same sound in two different positions? Mr. ROWLAND. This is due to a long study of sound and study of echo effects. Mr. SPECTER. When had you conducted that study? Mr. ROWLAND. In physics in the past 3 years. Mr. SPECTER. Have you read any special books on that subject? Mr. ROWLAND. Quite a few. Mr. SPECTER. Do you recollect any of the titles and authors? Mr. ROWLAND. No; I do not. Mr. SPECTER. Did you take any special courses which would give you insight into that subject matter? Mr. ROWLAND. This was more or less on my own initiative. The instructor gave me help and aided me when I requested this during my off periods of class. Mr. SPECTER. What instructor was that? Mr. ROWLAND. His name was Foster. Mr. SPECTER. Do you recall his first name? Mr. ROWLAND. Sam. Mr. SPECTER. And at what school does he teach? Mr. ROWLAND. He teaches at Crozier Tech, Downtown Technical High School. Mr. SPECTER. Is he still there? Mr. ROWLAND. To my knowledge. Mr. SPECTER. How recently did you have a course with him? Mr. ROWLAND. Last year, last school year. Mr. SPECTER. Can you describe the second sound by comparison with the first sound which you have described as being similar to a backfire? Mr. ROWLAND. The second to my recollection was identical or as closely as could be. Mr. SPECTER. How about the third shot? Mr. ROWLAND. The same. Mr. SPECTER. Sounded the same to you? Mr. ROWLAND. Yes. Mr. SPECTER. Did you have any impression or reaction as to the point of origin when you heard the first noise?