The accurate investigation of the lowest forms of animal life, commenced by Leeuwenhoek and Swammerdam, and continued by the remarkable labours of Reaumur, Abraham Trembley, Bonnet, and a host of other observers in the latter part of the 17th and the first half of the 18th centuries, drew the attention of biologists to the gradation in the complexity of organization which is presented by living beings, and culminated in the doctrine of the echelle des titres, so powerfully and clearly stated by Bonnet, and, before him, adumbrated by Locke and by Leibnitz.
De Reaumur, and (1752-1778) of the Swede C. de Geer.
The work of de Reaumur and de Geer on the bionomics and life-history of insects has been continued by numerous observers, among whom may be especially mentioned in France J.
We note the names of Vallisnieri (1661-1730) and Alexander Monro (1697-1767); the travellers Tournefort (1656-1708) and Shaw (1692-1751); the collectors Rumphius (1637-1706) and Hans Sloane (1660-1753); the entomologist Reaumur (1683-1757); Lhwyd (1703) and Linck (1674-1734), the students of Star-Fishes; Peyssonel (b.
1694), the investigator of Polyps and the opponent of Marsigli and Reaumur, who held them to be plants; Woodward, the palaeontologist (1665-1722) - not to speak of others of less importance.
The general plan of the open-hearth process was certainly conceived by Josiah Marshall Heath in 1845, if not indeed by Reaumur in 1722, but for lack of a furnace in which a high enough temperature could be generated it could not be carried out until the development of the Siemens regenerative gas furnace about 1860.
It is true that Reaumur in 1722 described his method of making molten steel in crucibles, and that the Hindus have for centuries done this on a small scale, though they let the molten steel resolidify in the crucible.
The classical observations of Reaumur Memoires pour servir a l'histoire des insectes, vols.
De Reaumur, who "would willingly refer to the class of insects all animals whose form would not allow them to be placed in the class of ordinary quadrupeds, in that of birds, or in that of fishes.
Huber found that although he could induce swarms to occupy the glass-sided single frame advised by Reaumur, if the frame was fitted with ready-built pieces of comb patched together before hiving the swarm, the experiment was successful, while if left to themselves the bees built small combs across the space between the sheets of glass, and the desired inspection from the outside was thus rendered impossible.
On the Fahrenheit scale the points are respectively 3 2° and Zia °; on the Centigrade scale they are o° and roo°; and on the Reaumur they are o° and 80°.