# The Moving Picture Boys on the Coast/Chapter 11
#### CHAPTER XI
##### A STRANGE CHARGE

"Are you going to take a camera with you, boys?" asked Mr. Ringold, as Joe and Blake were saying good-bye to their friend, preparatory to making a brief stay in San Francisco.
"A camera? No. Why?" inquired Blake.
"Well, I happen to need some San Francisco street scenes for one of the dramas," went on the theatrical man; "and it occurred to me that you could get them when you weren't busy."
"Of course we could," answered Joe. "We can take the automatic, and set it up wherever you say, and go looking for that shipping agent. When we come back we'll have all the pictures we need."
"Good!" exclaimed Mr. Ringold. "Try that, if you don't mind. Get some scenes down in the financial district, and others in the residential section. Then, as long as you have to go to the shipping offices, get some there."
​The boys promised they would, and added the small but compact automatic camera to their luggage as they started off.
This camera worked by compressed air. There was a small motor inside, operated by a cylinder of air that could be filled by an ordinary bicycle pump. Otherwise it was just like the other moving picture cameras.
There was the upper box, in which was wound the unexposed reel of film. From this it went over a roller, and the cog wheel, which engaged in the perforations, thence down by means of the "gate," behind the lens and shutter. There two claws reached up and grasped the film as the motor operated, pulling down three-quarters of an inch each time, to be exposed as the shutter was automatically opened in front of the lens.
Each one of the thousands of moving pictures, as I have explained in previous books, is three-quarters of an inch deep, though, of course, on the screen it is enormously enlarged.
After the film has been exposed, three-quarters of an inch at a time, it goes below into another light-tight box of the camera, whence it is removed to be developed and printed. The movement of the film, the operation of the claws and the opening and closing of the shutter, making it ​possible to take sixteen pictures a second, was, in this camera, all controlled by the air motor.
Joe and Blake found much to amuse them in San Francisco, which they had never before visited. They were a bit "green," but after their experiences in New York they had no trouble in finding their way around.
"We'd better go to some hotel, or boarding house," suggested Joe, after their arrival. "Pick out one where we can leave the camera working while we're gone."
They did this, being fortunate enough to secure rooms in a good, though not expensive, hotel near the financial district. One of their windows looked directly out on a busy scene.
"That'll be just the place, and the sort of scene Mr. Ringold wants," declared Blake. "Let's set the camera there on the sill and see what it gets. The light is good to-day."
It was, the sun shining brightly, and being directly back of the camera, which would insure the proper illumination.
They adjusted the machine, and set the mechanism to go off about an hour after they had left the room. Then they went to find the shipping agent, to see if they could get any news of Joe's father.
But, to their disappointment, he was out, and ​none of the clerks could tell them what they wanted to know. They were directed to return the next day.
"More disappointment!" exclaimed Joe. "It does seem as if I was up against it, Blake."
"Oh, don't worry. To-morrow will do just as well as to-day. And you don't want to get in C. C.'s habit, you know."
"No, that's right. Well, what shall we do?"
"Let's look around a bit, and then go see how the camera is working."
They found so much to interest them in the streets of San Francisco that they did not go back to the hotel as soon as they had intended. When they did reach the street on which it stood they saw a crowd gathered.
"Look at that!" cried Blake.
"Yes! Maybe it's a fire!" exclaimed Joe. "Our camera——"
"There's no fire, or else we'd see some smoke," answered his chum. "But we'll see what it is. There's been some sort of an accident, that's sure."
They broke into a run, pushing their way through the throng about the front doors of the hotel. As they entered the lobby, they were surprised to see the clerk point his finger at them, and exclaim:
​"There are the two lads now!"
Everyone turned to look at Joe and Blake, and a man, dressed in some sort of uniform, approached them.
"Are you the lads that have rooms sixty-six and sixty-seven?" he asked, sharply.
"Yes," replied Blake.
"Why, has anything happened there?" asked Joe.
"Well, yes, there has, and we thought perhaps you could explain."
"Have we been robbed?" burst out Blake.
"Robbed? No," answered the clerk. "But——"
"Perhaps I had better explain," put in the uniformed man. "I think I shall have to ask you boys to come with me," he went on.
"Come where?" Joe wanted to know.
"To police headquarters."
"What for?" burst out Blake. "We haven't done anything! We only came here to——"
"Be careful," warned the man in uniform. "Whatever you say may be used against you."
"Why—why?" stammered Joe. "What's it all about?"
"An infernal machine!" exclaimed the hotel clerk. "How dare you poke one out of the window, right toward one of our largest banks, and ​go out, leaving the mechanism clicking? How dare you?"
Joe and Blake staggered back, half amused and half alarmed at the strange charge.