Joe Strong was in two minds as he heard this warning and observed the face of the man he was befriending.  His first thought was that Ham had broken his promise and was indulging in intoxicants.  Naturally the man would want to conceal this as long as possible.  The other thought was that the tramp fire-eater was up to some trick—­perhaps he was jealous of Joe’s success and his own failure and wanted to spoil some of Joe’s apparatus.  Yet Joe did not recognize as any of his property the brown bottle, which when broken emitted such a queer smell.

Joe decided to investigate further, and so, not heeding the warning call of the former circus star, he walked closer to the broken flask.

“Keep away from that!” cried Ham sharply.  “Keep away!”

“Why?” asked Joe, with equal insistence.

“Because it’s dangerous,” was the answer.  “Very dangerous.”

“Dangerous for you or me?” Joe wanted to know.  “Look here, Ham,” he said earnestly, “are you up to—­any of your old tricks?  You know what I mean.  Are you?”

The man flushed.  Then, looking Joe straight in the face, he said: 

“You have a right to ask that, and I’ll answer you as straight.  I haven’t broken my promise—­that is, only the times you know about.  I haven’t broken it this time.  I found that bottle in among your things, and I was mighty sure it didn’t belong there.”

“What’s in the bottle?” asked Joe, for, though he had dabbled in chemistry, he did not recognize the queer odor.

“A combination of the strongest acids ever known!” was the answer of Ham Logan.  “A drop of it makes a terrible burn, and it will eat through solid steel and iron.  I knew that if it broke where it was, among your trick things, a lot of them would be ruined.  And I knew you couldn’t have left the bottle there by mistake, as it wasn’t there the last time I packed away your duds.  And I knew if you knew what it was you wouldn’t have left it around in that careless way.  So, taking no chances, I threw it away, and I meant to break the bottle.  That acid is awful stuff.  It’s best to let it soak into the ground.  Come over and see what it does even to earth and stones.”

He led the way to where the fluid had escaped from the broken flask, the fragments of which were scattered about.  The odor was less strong now, as the acid was soaking into the earth.  But there was a fuming and bubbling at the spot, and the very stones and earth seemed to be burning up in a small area.

“Don’t step in it!” warned Ham Logan.  “It will eat right through your shoes.  Glass is the only thing it won’t hurt—­glass and porcelain.  They mix it in porcelain retorts.  I’ll throw some loose earth over this place.  The effects of the acid will soon be lost, but while it’s active it’s terrible stuff, believe me!”

“And you say you found that bottle in my baggage?” asked Joe.

“Yes,” answered Ham Logan.  “And am I right in saying you didn’t know it was there?”