And, after they had eaten, Tom got out some of his toys, and he and Flossie and Freddie had a good time playing about the house and in the yard.  The stray cat wandered away while Flossie and Freddie were eating their little lunch, and the Bobbsey twins did not see him again.

Now while Flossie and Freddie were having a pretty good time, eating cookies and drinking milk, there was much excitement on the big sight-seeing car where Mr. and Mrs. Bobbsey, Nan, Bert, and the other, still had their seats.

For some little time after the car had stopped to allow the man to put water in the radiator, neither Mr. nor Mrs. Bobbsey missed their smaller twins.  They were busy talking, and Bert and Nan were looking about and having a good time, talking to Billy and Nell Martin.

At last, however, the auto man called: 

“Everything is all right!  Get on board!”

That meant he was going to start off again, and it was not until then that Mrs. Bobbsey thought to look around to see if Flossie and Freddie were all right.  And, of course, she did not see them.

“Flossie!  Freddie!  Where are you?” called Mrs. Bobbsey.

There was no answer, and the seat which the two smaller children had been in on the big bus, was empty.

“Oh, Daddy!” cried Mrs. Bobbsey, “Flossie and Freddie have gone.”

“Gone?  Gone where?” Mr. Bobbsey asked,

“That’s it—­I can’t say,” answered Mrs. Bobbsey.  “The last I saw of them was when the auto stopped.”

“I saw the two little tots climb down off the rear steps of the car,” said the man who had wanted to “stretch his legs.”  “They seemed to be going after something,” he added.

“It was a cat,” said the woman next to the big man who had last spoken.  “I saw the children get down and go toward a stray cat and then I got to thinking of something else.”

“Oh, if it was a cat you might know it!” exclaimed Mrs. Bobbsey with a laugh.”  I guess they’re all right.  They can’t have gone far.  Probably they are on the other side of the street, looking at some bedraggled kitten.”  But a look up and down the street did not show Flossie and Freddie.  By this time the auto was all ready to start off again.

“But we can’t go without Flossie and Freddie!” cried Nan.

“I should say not!” exclaimed Mrs. Bobbsey.  “Oh, where are they?  Where can my darlings have gone?  What has happened?”

CHAPTER XVI

THE FIRE BELL

Mrs. Bobbsey’s cries of alarm, of course, excited all the other passengers who had got back on the sight-seeing auto, ready to start off again.  They had had a little rest while the water was being put into the radiator, and the man had “stretched his legs” all he wanted to, it seemed.

“The children can’t be far away,” said Mr. Bobbsey.  “They were here only a moment ago.  Even if they have wandered off, which is probably what they have done, they can’t be far.”