The increase in life expectancy during the 20th century is largely due to improvements in child survival; this increase is associated with reductions in infectious disease mortality, due largely to immunization.1 However, infectious diseases remain a major cause of illness, disability, and death.
The First Mowers. The lawn mower was invented in 1830 by Edwin Beard Budding, an engineer from Stroud, Gloucestershire, England. He obtained the idea after seeing a machine in a local cloth mill which used a cutting cylinder (or bladed reel) mounted on a bench to trim cloth to make a smooth finish after weaving.
Rotary mowers: The rotary mower, which is the primary type of mower for many homeowners, is most effective at cutting grass to a height of one-and-a-half to three inches. It works by using a high-speed, rotating blade to cut the grass.These mowers are noisy, but they are easier to sharpen and maintain than reel mowers. Proper mowing practices are fundamental to achieving a healthy, green lawn. A properly mowed lawn will have healthier, denser grass and fewer weeds.eel mowers: This type of mower works best on grass with short heights of one inch or less, such as Bermuda or zoysia grass. It uses a shearing action to cut the grass.