"This is a good rule to remember," said the photographer. "Never open the shutter of your camera until you are certain you are ready to take the picture, and never attempt to develop a plate or a film until you are sure your chemicals are properly mixed, and until you are sure you have everything at hand with which to work, and until you are sure the plate or film is properly protected from the light."
The boys were surprised when Mr. Jally announced that it was supper time and that he must go home.
"Gracious! And I told my aunt we'd be to supper by six o'clock!" exclaimed Shep. "We'll have to leg it to her house."
"Come again to-morrow at nine o'clock," said the photographer, and this the chums promised to do.
"Well, I've learned a whole lot to-day," said Snap as they walked along. "I am sure I can take a much better picture than formerly."
"And I've learned one little lesson," came from Whopper. "After this I am not going to take so many snapshots of landscapes. I am going to take time exposures, and put my camera on a tripod, and study the scene through the ground glass, to get the best view possible."
Mrs. Carson, the doctor's sister, had given the boys their dinner, and now she had supper on the table waiting for them. Their experiments of the afternoon had made them hungry, and all "pitched in" with a vigor that made the good woman smile.
"What do you intend to do this evening?" she asked.
"We are going to the circus, Aunt Jennie," answered Shep. "Father said we might go."
"I thought as much. Don't stay out too late."