[See also: Cats and Dogs May See in Ultraviolet] Like the human retina, the canine retina contains other kinds of photoreceptors in addition to cones, called rods. These light receptors do not perceive color, but they are sensitive to light and dark changes, as well as shape and movement. And the ratio of rods to cones in the retina is much higher in dogs than it is in humans.
The distance between rungs, cleats, and steps shall not exceed 12 inches and shall be uniform throughout the length of the ladder. 1910.27(b)(1)(iii). The minimum clear length of rungs or cleats shall be 16 inches.
Be sure that both rung hooks lock securely onto a rung of the ladder, then tie off the end of the rope to a lower rung. â¢ To set the proper ladder angle, use a 1:4 ratio: Divide the ladder height by 4, then move the ladder base that far from the house. For example, if the ladder is 16 feet tall, its base should be 4 feet away from the house. â¢ Both ladder feet should sit firmly on the ground.