Many pencils across the world, and almost all in Europe, are graded on the European system using a continuum from H (commonly interpreted as “hardness”) to B (commonly “blackness”), as well as F (usually taken to mean “fineness”, although F pencils are no more fine or more easily sharpened than any other grade. also known as “firm” in Japan[45]). The standard writing pencil is graded HB.[46]
According to Petroski, this system might have been developed in the early 20th century by Brookman, an English pencil maker. It used B for black and H for hard; a pencil’s grade was described by a sequence or successive Hs or Bs such as BB and BBB for successively softer leads, and HH and HHH for successively harder ones.[47]
The Koh-i-Noor Hardtmuth pencil manufacturers claim to have originated the HB standard of gradations, with H standing for Hardtmuth, B for the company’s location of Budějovice, and F for Franz Hardtmuth, who was responsible for technological improvements in pencil manufacture.[48][49]
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Insect collecting refers to the collection of insects and other arthropods for scientific study or as a hobby. Because most insects are small and the majority cannot be identified without the examination of minute morphological characters, entomologists often make and maintain insect collections. Very large collections are conserved in natural history museums or universitieswhere they are maintained and studied by specialists. Many college courses require students to form small collections. There are also amateur entomologists and collectors who keep collections.
The Phasmatodea are an order of insects, whose members are variously known as stick insects (in Europe and Australasia), walking sticks or stick-bugs (in the United States and Canada), phasmids, ghost insects and leaf insects (generally the family Phylliidae). The ordinal name is derived from the Ancient Greek φάσμα phasma, meaning an apparition or phantom, and refers to the resemblance of many species to sticks or leaves. Their natural camouflage can make them extremely difficult to spot. Phasmatodea can be found all over the world in warmer zones, especially the tropics and subtropics. The greatest diversity is found in Southeast Asia and South America, followed by Australia. Phasmids also have a considerable presence in the continental United States, mainly in the Southeast.
