An hourglass (sandglass, sand timer, sand clock, egg timer) measures the passage of a few minutes or an hour of time. It has two connected vertical glass bulbs allowing a regulated trickle of material from the top to the bottom. Once the top bulb is empty, it can be inverted to begin timing again. The name hourglass comes from historically common hour timing. Factors affecting the time measured include the amount of sand, the bulb size, the neck width, and the sand quality. Alternatives to sand are powdered eggshell and powdered marble (sources disagree on the best material). In modern times, hourglasses are ornamental, or used when an approximate measure suffices, as in egg timers for cooking or for board games.

The origin of the hourglass is unclear, although it may have been introduced to Europe by an 8th-century monk named Luitprand, who served at the cathedral in Chartres, France. It was not until the 14th century that the hourglass was seen commonly, the earliest firm evidence being a depiction in the 1338 fresco Allegory of Good Government by Ambrogio Lorenzetti. Unlike its predecessor the clepsydra, or water clock, which may have been invented in ancient Egypt, the hourglass is believed to have originated in medieval Europe. This theory is based on the fact that the first written records of it were mostly from logbooks of European ships. Written records from the same period mention the hourglass, and it appears in lists of ships stores. An early record is a sales receipt of Thomas de Stetesham, clerk of the English ship La George, in 1345:

Dave Gahan ( /ˈɡɑːn/; born 9 May 1962) is an English singer-songwriter, best known as the baritone lead singer for the British electronic music band Depeche Mode since their debut in 1980. He is also an accomplished solo artist, releasing albums in 2003 (Paper Monsters) and 2007 (Hourglass). Despite his bandmate Martin Gore continuing to be the main Depeche Mode songwriter, Gahan has contributed a number of songs to the band's most recent albums, Playing the Angel (2005) and Sounds of the Universe (2009). Two of these songs were released as singles, including "Suffer Well" in 2006 and "Hole to Feed" in 2009. Q magazine ranked Gahan no. 73 on the list of the "100 Greatest Singers" and no. 27 on "The 100 Greatest Frontmen".

David Gahan was born into a working class family, to parents Len Callcott^{[citation needed]} (a bus driver) and his wife Sylvia (a conductress or "clippy" on London's buses), Dave was six months old when his father left the family. Sylvia and Len divorced two years later and his mother moved Dave and sister Sue (born 1960) to Basildon, Essex, after Sylvia met and married her second husband Jack Gahan (an administrator with Shell Oil). The Gahan family continued to grow with the birth of two more brothers Peter (born 1966) and Phil (born 1968). Dave and Sue were raised under the impression that their mother's second husband, Jack, was their natural father.

Duane Allman (born Howard Duane Allman; November 20, 1946 – October 29, 1971) was an American guitarist, session musician and the primary co-founder and leader of the The Allman Brothers Band, until his early death in a motorcycle accident in 1971 at the age of 24.

ABB was formed in 1969 and, unusually for the time, based in the Southeastern United States. In the early 1970s the band was hugely successful. Duane is best remembered for his brief but influential tenure in that band and in particular for his expressive slide guitar playing and inventive improvisational skills. In 2003, Rolling Stone magazine ranked Allman at #2 in their list of the 100 greatest guitarists of all time, second only to Jimi Hendrix and in 2011 he was ranked #9. His tone (achieved with a Gibson Les Paul and two 50-watt bass Marshall amplifiers) was named one of the greatest guitar tones of all time by Guitar Player.

A sought-after session musician both before and during his tenure with the band, Duane Allman performed with such established stars as King Curtis, Aretha Franklin, Wilson Pickett, and Herbie Mann. He also contributed heavily to the 1970 album Layla and Other Assorted Love Songs by Derek and the Dominos.

Rodrigo Amarante de Castro Neves (born September 6, 1976), in (Rio de Janeiro, Rio de Janeiro (state), Brazil) is a guitarist, occasional bassist, singer and songwriter for the bands Los Hermanos, Orquestra Imperial and Little Joy.

He studied Journalism at PUC-Rio, where he met Marcelo Camelo and Rodrigo Barba. After a few rehearsals with Los Hermanos, he was invited to join the band.

In their debut album, Los Hermanos (1999), Amarante contributed very little, playing transverse flute and doing the backing vocals. And there are only two songs written by him: "Quem Sabe" (Who Knows), which turned out to be one of the CD's singles, and "Onze Dias" (Eleven Days).

In the band's second album, Bloco do Eu Sozinho (2001), Amarante was able to show his real musical quality, playing guitar together with Marcelo, and writing more songs. He recorded "Sentimental" (considered by Dado Villa-Lobos from Legião Urbana as the best song of 2001), "Retrato pra Iaiá" (Portrait for Iaiá), and "Cher Antoine" (sung in French). He also wrote the instrumental part of the song "Mais Uma Canção" (One More Song) with Marcelo. And, together with Marcelo, he wrote "A Flor" (The Flower), one of the album's hits.