For air-dry wood the ratios are considerably lower, particularly in the case of the ultimate strength and the elastic limit.
The ultimate strength of concrete in compression was taken as 2,000 lbs.
The ratio of the ultimate strength to the working strength is called the factor of safety.
The importance of the gelatine as a factor in the ultimate strength is thus clearly and strikingly demonstrated.
In the case of curved steel wire pulled straight, its ultimate strength was found to be only about 90 per cent.
But the plans for its development contemplate an ultimate strength of 425,000 men.