He was a tall man and a very thin one, and as he stood in the doorway peering into the Model Garage shop Gus Wilson noticed that he was lighting a fresh cigarette from one that wasn't more than half smoked.  The hand that held the stub was shaky.  "Poor guy's got the jitters about something," Gus remarked mentally.

"Well, a lot of people have a right to have the jitters these days."  He gave the visitor his usual friendly grin and asked, "Something I can do for you?"

The tall man's lips jerked into an answering smile as he came into the shop.  "You're Gus Wilson, I take it," he said.  "My name's Williams - Henry R. Williams.  I'm the super at that United Machine Corporation plant a few miles down the road, and I'm living at the Park House until I can find some place to move my family.  I've seen you in the dining room down there.  The manager told me that you might be able to help me out."

"I'd be glad to Mr. Williams," Gus told him heartily.  "What is it you want me to help you out of?"

"I'm having gasoline trouble," Williams announced gloomily.

Gus laughed.  "So's everybody," he said.

"What's your particular brand of gasoline trouble?"

"Not being able to get enough of it," Williams told him.  "We're working three shifts on a government contract and I have to make two round trips per day between the Park House and the plant.  The rationing board here gave me what they said would be enough coupons to see me through, but I've used all but four of them, and there are still almost two weeks to go.

"Of course, I applied for more gas yesterday, but they turned me down.  Trouble is, they figure 15 miles to a gallon and - believe it or not - I can't get over 10 miles a gallon out of my car.  It isn't a big bus, either - just an ordinary '41 six-cylinder sedan.  I ought to get 16 or 17 miles at least.

"Funny thing about it all is that I can't find anything wrong with the car.  It runs as well as it did the day I bought it.  Must be the fault of the gas they're selling these days - it's terrible!"

"Gas isn't what it used to be.  There's no doubt about that," Gus agreed.  "But it isn't bad enough to account for your getting only 10 miles a gallon out of a job which ought to give you 50 percent more mileage than that.  Got your car outside?  Good.  Suppose you drive it in and let me have a look at it."

Williams ran his sedan into the shop and got out.  "How's your lubrication?" Gus asked him.

"It should be all right," Williams said.  "I had the car greased only last week, at the same time I had the oil changed."

"Good enough," Gus told him.  "Then it isn't at all likely that it's friction that's wasting your fuel.  But there are a lot of other things that make a bus burn more gas than it should.  Maybe none of them is the matter with your car, but I'll do a little checking to make certain of that.  How long is it since you had your spark plugs cleaned and adjusted?"

"Oh, maybe a month," Williams told him after a moment's thought.  "No, it's a little longer than that - maybe two months.  But I never miss on having that attended to every 5,000 miles."

"Two months," Gus said.  "Your plugs should be all right then.  But I'll have a look at them anyhow - they foul up very quickly with some of the gasoline we're getting.  Bad plugs are vicious fuel wasters.  Maybe you remember reading about those taste they ran out at the University of Michigan a couple of years ago - they showed that bad plugs waste one gallon of gas out of every 10 you put in your tank."

He checked the plugs carefully.  Then he shook his head.  "They are all giving a good, hot spark," he reported, "and that's all you can ask of any spark plugs.  Well, let's see."

Working with the seeming casualness with which he camouflages his close attention to every detail.  Gus checked the fuel line.  He found no leaks in it.  He examined the octane selector.  It was set properly.  Then he had a look at the carburetor jets.  They were clean.

He straightened up, pulled his pipe out of the overalls pocket, filled and lighted it.  Then he grinned at Williams, who was making no attempt to cover up the fact that he was rapidly losing his patience.  "So far - no explanation," Gus observed calmly.  "Your car seems to be in first-class condition.  Of course, there may be a compression leak in one of the cylinders, but that wouldn't altogether account for such high fuel consumption.  Let's get scientific and find out exactly what mileage you're getting.  I'll hook on a mileage tester - it's one of the instruments my partner, Joe Clark is always accusing me of liking to play with.  Then, if you have the time, let's go out and take a ride."

"I'm a busy man, and I haven't any time to waste!"  Williams snapped.  "But I've got to get this car fixed so that it will burn less gas, so if you think you can do the job, go ahead and do it your own way.  All I ask for is results!  Meanwhile, I've got to call the plant.  Where's your phone?"

"Right in there," Gus said placidly, pointing toward the office door with the stem of his pipe.

When Williams came out of the office a few minutes later, he found Gus in the driver's seat of the sedan.  "Hop in, Mr. Williams," he called, "and we'll find out what this bus of your really can do."

Williams got in, and Gus backed out of the shop and drove slowly up the road.  When a bout a mile out of town, they came to a straight, almost level stretch of highway, he pressed his foot slowly down on the accelerator until the speedometer registered 30 miles per hour.  There was so little traffic on the road that they had it almost to themselves.  Gus held the speed steadily at 30 for 10 minutes.  The mileage tester showed 23 miles per gallon!"

Williams lighted another of his endless chain of cigarettes and puffed nervously for a few seconds.  "Twenty-two miles!" he broke out.  "That's impossible, I tell you!

Either that fool tester of yours is screwy, or you're crazy.  Oh, I'm sorry, Mr. Wilson - my nerves are all shot.  But if you can't think of any more sensible way of trying to find out what's the matter with my car than - "

"Let's give the tester another chance," Gus interrupted coolly.  He swung the car around easily and headed back toward town.  There still wasn't enough traffic to bother them, but now they were climbing a very slight grade.  The tester showed a fuel-consumption rate of a gallon for 21 miles.

"That doesn't prove anything," Williams insisted.  "Even if that tester is accurate - and I don't believe it is! - the conditions are altogether different.  Out here we're on an almost level road with very little traffic.  But between the Park House and our plant it's all up and downhill, and the traffic is heavy, and there are a lot of stoplights.  You can't say that this is really a conclusive test at all, Wilson."

"I know," replied Gus, "I was thinking about that too.  How's this for an idea?  Supposing I meet you at the Park House after dinner this evening, and we make the round trip from there out to your plant and back just the way you make it twice a day, and then see what the tester shows?"

"Well," agreed Williams, a little slowly, "I just have to find out what ails this blasted car of mine.  I've rather lost faith in that little tester you seem so proud of - oh well, I guess we'd better give it a fair chance.  Yes, I'll meet you this evening around seven o'clock."

Gus finished eating a leisurely meal at the Park House and found Williams impatiently pacing the length of the lobby.  "Thought you weren't coming after all," he grumbled, as Gus strode toward him, pipe in mouth and grinning amiably.

"Oh, I always keep appointments," laughed Gus, "but I enjoy my food, too - and I don't like to eat fast."

The two of them went out and climbed into Williams's sedan.  "You drive this time," said Gus.  "By the way, how long has your car been standing?"

"Two hours," the other told him.

"Then we're starting the trip with a cold engine the same way you start most of your trips," Gus said.  "That accounts for some part of your high fuel consumption - when you start a short drive with a cold engine, your fuel mixture stays rich for most of the trip.  Still, that wouldn't account for the amount of gasoline your car uses.

"Well, suppose we start.  We'll have to get this mystery solved sometime.  I always say there's no time like the present when there's a trouble-shooting job on the fire."

Traffic along the highway was very heavy.  Busses, trucks, taxis, and a few private care filled the road.  Williams started out with a terrific lunge; then, driving as fast as he could, he curved in and out of the traffic.  When a red light forced him to stop, he kicked on the brakes hard, almost jerking Gus out of his seat, and when he started again he accelerated rapidly.  Gus, sitting beside him, smiled inwardly but held his peace.  The mileage tester now showed the rate of fuel consumption to be a gallon for 10 miles.

"Aha!" said Williams triumphantly.

"Didn't I tell you!  Now that tester of yours is working right!"

"Tell you what," Gus answered, "let's turn around and go back to town.  This time, let me drive."

Conditions on the road were almost exactly the same as they had been on the trip out to the plant.  Gus however, kept the speed of the car at a steady 30 miles an hour.  When he had to use the brakes, he applied them as gently as possible, and then accelerated very gradually to regain speed.  A glance at the mileage tester showed that this time they had used gasoline at the rate of a gallon for 16 miles.

Mr. Williams tilted his hat far back on his head, lit still another cigarette, and sputtered, "But - but I don't understand it!  It's the same road the same car.. Wilson, what's the answer?"

Gus chuckled.  "Well," he said, "if you don't mind my saying so, the matter isn't with the car or the road at all.  The matter is with you."

"With me!" exclaimed Williams.  "What do you mean - with me?"

"Take it easy," said Gus, cheerfully.  "You haven't committed a crime - exactly.  You're just in too much of a hurry, that's all."

William's rather tense expression relaxed just a little.  "Well, I'll be - " he said.  "Do you mean to say that my driving causes that much difference in the gasoline consumption?"

"That's about it," replied Gus.  "You see, you waste just about one third of your power and gasoline by accelerating too fast when you want to go and braking too severely when you have to slow down.  It's a case of nerves, Mr. Williams, gasoline jitters, we'll call it.  Use your head, take it easy, and see if you won't get 15 miles to a gallon out, of your bus."

"You know, Wilson," replied Williams earnestly. "If I hadn't seen this little demonstration with my own eyes I'd never have believed it.  And what's more I would have put up a pretty big argument to prove you were wrong.  But this time the proof of the pudding is in the seeing, I guess.  Anyway, I certainly appreciate all your trouble.  And I'll certainly take your darned good advice."

"Good!" beamed Gus.  "Glad I could be of service.  And don't forget - those jitters of yours are pretty expensive.  The less you have 'em, the more gasoline you'll have!"

END