Pontoon bridge transport soldiers and artillery across rivers in the South. In 1872 at a military review before Queen Victoria, a pontoon bridge was thrown across the River Thames at Windsor, Berkshire, where the river was wide. The bridge, comprising 15 pontoons held by 14 anchors, was completed in 22 minutes and then used to move five battalions of troops across the river. It was removed in 34 minutes the next day. The British Blanshard Pontoon stayed in British use until the late 1870s, when it was replaced by the "Blood Pontoon". The Blood Pontoon returned to the open boat system, which
Acoustic suspension acoustic suspension, with a separate, sealed air-space, even if the woofer itself is not. One notable exception to this was the Sonus Faber Stradivari Homage which uses a ported enclosure for the midrange. The two most common types of speaker enclosure are acoustic suspension (sometimes called pneumatic suspension) and bass reflex, so they are worth comparing. In both cases, the tuning affects the lower end of the driver's response but above a certain frequency, the driver itself becomes the dominant factor and the size of the enclosure and ports (if any) become irrelevant. In general, acoustic suspension systems (driver +