October 5, 1852, and remained valid despite numerous attempts to challenge it based on its alleged use of prior art. Langstroth made many other discoveries in beekeeping and contributed greatly to the industrialization of modern beekeeping. Other inventors, notably François Huber in 1789, had designed hives with frames (the so-called or book hive), but Langstroth's hive was a practical movable frame hive, which overcame the tendency of the bees to fill empty spaces with comb and to cement smaller spaces together with propolis. In contrast to August von Berlepsch's frame-movable side-opened hive (May 1852, Germany), Langstroth's hive was top-opened, as was the Bevan top-bar hive (1848, UK). These combined adaptations led to the Langstroth hive design being preferred by beekeepers over all others, and variations on his hive are used throughout the world. Langstroth subsequently published a book called A Practical Treatise on the Hive and Honey-Bee, nowadays commonly known as The Hive and the Honey Bee or, under the title with which it was re-issued in 2004, as Langstroth's Hive and the Honey-Bee: The Classic Beekeeper's Manual. In this book, Langstroth described the proper dimensions and use of the modern beehive as we know it today. Langstroth's book went through several editions until about 1900, but in all of them the hive that is illustrated is the same as the original design. Bee space A dimension of 7 ± 2 mm ( or roughly ) is nowadays the usual size meant when bee space is referred to. This setup has been established for the brood chamber, as for honey storage the comb distance can be different. Dr. Jan Dzierżon, a Polish apiarist, had in the year 1835 determined the correct spacing for the top-bars in beehives. The distance between combs had been described as from the center of one top-bar to the center of the next one. In this case, the distance between combs is ; that is, twice the medium bee space of . Later, in 1848, Dzierżon introduced grooves into his hives' side walls, to replace the strips of wood that the top-bars had earlier been hung from. The grooves were . In Europe, both Dzierżon and fellow apiarist Baron August von Berlepsch had been focused on side-opened hives. Land resources for beekeeping was limited, and traditionally multiple bee hives had been kept in a single beehouse. The so-called bee space had been incorporated by Berlepsch into