Among tear gases, the new chloracetophenone, a solid, is perhaps the greatest of all. When driven off by heat it first appears as a light bluish colored cloud. This cloud is instantly so irritating to the eyes that within a second anyone in the path of the cloud is temporarily blinded. It causes considerable smarting and very profuse tears which even in the smallest amount continue for two to five minutes. In greater quantities it would continue longer. So far as can be ascertained, it is absolutely harmless so far as any permanent injuries are concerned. Considering that it is instantly effective, that minute quantities are unbearable to the eyes, that it can be put in hand grenades or other small containers and driven off by a heating mixture which will not ignite even a pile of papers, and that it needs no explosion to burst the grenade (all that is used is a light cap, set off by the action of the spring, sufficient to ignite the burning charge), the future will see every police department in the land outfitted with chloracetophenone or other similar grenades. Every sheriff’s office, every jail and every penitentiary will have a supply of them. No jail breaking, no lynching, no rioting can succeed where these grenades are available. Huge crowds can be set to weeping instantly so that no man can see and no mob will continue once it is blinded with irritating tears. More than that, it is an extremely difficult gas to keep out of masks, ordinary masks of the World War being entirely useless against it. The same is true of diphenylaminechlorarsine. This is not a tear gas but it is extraordinarily irritating to the lungs, throat and nose, where it causes pains and burning sensations, and in higher concentrations vomiting. It is hardly poisonous at all so that it is extremely difficult to get enough to cause danger to life. This is mentioned because of its possible use for the protection of bank vaults, safes, and strong rooms generally. There are many other gases that can be used for this same purpose. It is presumed that gases that are not powerful enough to kill are the ones desired, and there are half a dozen at least that can be so used. If desired deadly gases can just as readily be used. Already a number of inventors are at work on the problem, with some plans practically completely worked out and models made. It has been suggested that one of these gases could be used by trappers in trapping wild animals. Hydrocyanic acid gas may be so used. It acts quickly and is very rapidly dissipated. An animal exposed to the fumes would die quickly and the trap be safe to approach within two minutes after it was sprung. It is said that the loss from animals working their way out of traps by one means or another is nearly 20 per cent. More than this, it would meet the objections of the S. P. C. A. in that the animal would not suffer from having its limbs torn and lacerated by the trap.