From the text (p.1) ... 'The Forest Service of the Department of the Interior has long recognized forest protection as one of the important problems facing the people of this country. Scientific methods of increasing forest wealth can avail little unless the trees can be preserved from destruction. A satisfactory degree of protection must, therefore, be attained by any forest organization before skilled methods of forest management can be expected to have any material effect in arresting forest depletion. The Forest Service has always endeavoured to keep abreast of all progress in what may now safely be called the science of forest protection, and in 1929 an intensive study was begun at the Petawawa Forest Experiment Station with a view to arriving at a more complete understanding of the natural phenomena relating to forest fires. The following paper is a brief discussion of some of the conclusions reached and the methods used in carrying on this study....'(p.2) ... 'We have standards, or units of measurement for practically everything, but no unit for measuring fire hazard. Some say, what is the need of such a unit? You will know a hazard exists when fire breaks out, and you must be always ready to handle such an emergency. Quite true, and so in war-time must a commanding officer be always ready to handle an enemy attack, but who will say that officer will not be in a better position if he knows the strength of the enemy and when and where to expect the attack? So in forest protection there is great need of a unit for measuring cumulative fire-hazard or inflammability, which will enable forest authorities to know what to expect each day and be in a position to make their plans accordingly. This paper deals with the development of such a unit of measurement, and the preparation of curves or tables by means of which daily weather measurements may be converted into units of fire hazard.'