Malus or seventh tree, or limbs of a crab tree are grafted onto some of the apple trees. In emergencies, a bucket or drum bouquet of crabapple flowering branches are placed near the beehives as orchard pollenizers. See also Fruit tree pollination. Because of the plentiful blossoms and small fruit, crabapples are popular for use in bonsai culture. Crabapple fruit is not an important crop in most areas, being extremely sour due to malic acid (which like the genus derives from the Latin name "mālum"), and in some species woody, and for this reason is rarely eaten raw. In some southeast
Étienne-Louis Malus index between the surface and the interior of the glass). It was not until 1815 that Sir David Brewster was able to experiment with higher quality glasses and correctly formulate what is known as Brewster's law. This law was later explained theoretically by Augustin Fresnel, as a special case of his Fresnel equations. Malus is probably best remembered for Malus's law, giving the resultant intensity, when a polariser is placed in the path of an incident beam. His name is one of the 72 names inscribed on the Eiffel tower. Étienne-Louis Malus Étienne-Louis Malus (; ; 23 July 1775 –