All are familiar with the application of such calculations in fire insurance. Among ten thousand houses a certain number will be destroyed by fire every year, provided those houses are widely distributed under essentially similar conditions. The ten thousand house owners can insure each owner against entire loss of his house by mutual agreement to meet their share of the total loss. If ten houses are burned, each of the ten thousand house owners will pay one-thousandth part of the total loss, making a burden easily provided for. If at the beginning of the year each has laid aside this sum, the loss will be met when it occurs without disturbing the welfare of any. The machinery for such provision is called an insurance company, and the separate payment of each house owner is the premium or award expressing his share of the provision. This principle of estimating losses and providing a definite way of meeting them is the same in all forms of insurance. It has been recognized for hundreds of years, but only recently has entered into the business life of the world in all directions. For a long time false notions of reverence for the power that wields destiny stood in the way of such distribution of misfortune; but now the mass of people everywhere regard such foresight in united sympathy as natural as the planting of crops. _Various methods of insurance._—Satisfactory insurance rests upon certain definite business principles which every insurer may wisely study. There are various devices for accomplishing the same end. A body of men sufficiently large to make the average of losses uniform may bind themselves by a simple agreement to meet each loss as it occurs. To make this plan satisfactory they will need efficient business men as officers to devise means and methods for making the agreement effectual, for estimating the actual loss in each case, and for distribution of the claim by assessment sufficient to cover the loss and the expense of collections and estimates, as well as the maintenance of the officers. These officers must maintain the business standing of the organization in the community, so that it shall continue for a long series of years to keep its numbers large enough to maintain only the average loss. This is a simple mutual insurance company, upon the assessment plan. Its weakness lies in the comparatively slight interest taken by each member in the selection of its officers, in the absence of security for the payment of assessments when needed, in the long delay liable to attend collections, and the uncertain interest of the officers in exact adjustment of losses. Such companies are liable to be too small to give a fair average of losses, and in any serious emergency to fail for want of expert business ability and trustworthy character in officers.