Occasions have arisen where a chemical expert has been asked to state whether a gun or pistol found lying near a body has or has not been recently discharged. Even in the case of firearms that had been loaded with black powder no very definite answer can usually be given to this question. Taylor suggested that the presence of potassium sulphide (formed from the powder) adhering to the barrel would indicate that the gun had recently been fired, whereas after a short time this sulphide would become oxidised, and no longer give the reactions of a sulphide. After a longer time traces of iron oxide formed from the iron of the barrel might be expected. It would not be safe to lay stress upon conclusions based upon such data as these, and at best they could only afford corroborative evidence. An amusing instance within the present writer's experience affords another example of the way in which a trifling point being overlooked may be strong presumptive evidence of attempted fraud. A family of the name of, say, Abendessig, effected an insurance against burglary with a company which may be described as the Safeguard Assurance Co. It was not long before they were the unhappy victims of a burglary in which Miss Abendessig lost several valuable pieces of jewellery including a watch, a diamond ring, and several brooches. In proof of her claim she produced receipts from the jeweller from whom she stated she had bought these articles, the total value of which was given at £150. There were three receipts in all, dated at intervals of two or three months, the first being made out to Miss Abendessig and the last to Mrs. Lab, she having been married in the interval, and the second to her father, Simeon Abendessig. The Safeguard Assurance Co. had a suspicion that the jeweller, who had an address but no shop, was in league with the Abendessigs, and that the first and third receipts had been written at the same time. The present writer was therefore asked to examine these documents to see whether any evidence of the date of writing could be obtained. They were both written in blue ink upon common billheads, but the fact that the ink and paper were of the same kind was no proof that they were not genuine receipts. When, however, the receipt stamps were examined under the microscope it was obvious that the right-hand side of one stamp corresponded with the left-hand side of the other stamp. That is to say, the little projections of paper left when two stamps are torn apart across the perforation exactly coincided in every instance, a long projection on one being matched by a short projection on the other, and so on. The exact coincidence of seventeen points could not have been the result of chance, and the stamps on the two receipts must therefore originally have been attached to one another in the sheet.