When a great crime has been committed the public mind experiences a sensation of horror. Imaginative persons are busy in the formation of all sorts of fancies with regard to the perpetrators. His probable appearance, gigantic proportions and horrible aspect are duly commented upon, and exaggeration invariably takes the place of fact in such estimations. In the majority of cases that have come under my notice the personal appearance of the criminal belied the possibility of his guilt.

The verdant spectator is frequently amazed to find the apparent gentleman, attired with the precision of the tailor's art, with immaculate linen, and of delicate, and sometimes refined appearance arraigned for the crime of robbery or murder.

Many times I have seen the eager spectator in a court-room, looking vainly among the group of lawyers before the bar, for the monster they have conjured up in their imaginations, and finally settling upon some sharp-featured, but unimpeachable attorney as the malefactor, indulge in wise reflections as to the impossibility of mistaking a rogue from his appearance.

I have seen their start of surprise as the real criminal, genteel, cool and gentlemanly, would rise from his seat and plead to the indictment that would be read to him, and their solemn shake of the head as their wise reflections were scattered to the winds.

My first experience with the town of Bridgeport was particularly suggestive of these reflections. I was engaged in a detective operation in which the Adams Express Company were the sufferers, having been robbed of a large amount of money, and, as the robbery took place in the vicinity of that city, the thieves, whom I succeeded in capturing, were confined in the jail there.

The affair occurred during the first week of January, 1866, and the facts were as follows:

On the night of the sixth of January, in the year just mentioned, the public mind was startled by the announcement that the Adams Express Company had been robbed of over a half million of dollars, by the thieves breaking into the car in which their valuables were placed, prying open the safes, and abstracting over six hundred thousand dollars, in notes, bonds and other valuable securities.

The train to which the car was attached had left New York for Boston at eight o' clock in the evening, and it was not until arriving at New Haven that the depredation was discovered.

The dismay of the company's officials may be imagined when, on entering the car at the latter place, the fractured safes met their astonished gaze. A marlin spike, three dark lanterns and a sledge hammer which lay beside them, told too plainly how the work had been accomplished, but it furnished no clue as to how, or when, or by whom.

The car was of the ordinary size of a box freight car, built with an iron frame, sheathed over with thick sheet iron plates, rivetted strongly together, and so closely made that a light placed inside could not be seen when the doors were closed. A messenger always accompanied this car, but he usually sat in the baggage car of the train, and as the train did not make any stoppages between New York and New Haven, it was only at this time that the theft was discovered by the entrance of the messenger.