Encyclopædia Britannica it is scarcely used, and reviewers have recommended that it be dropped from the encyclopaedia. The also has color transparencies of human anatomy and several appendices listing the staff members, advisors, and contributors to all three parts of the Britannica. Taken together, the and comprise roughly 40 million words and 24,000 images. The two-volume index has 2,350 pages, listing the 228,274 topics covered in the "Britannica", together with 474,675 subentries under those topics. The "Britannica" generally prefers British spelling over American; for example, it uses "colour" (not "color"), "centre" (not "center"), and "encyclopaedia" (not "encyclopedia"). However, there are exceptions to
Encyclopædia Britannica 2010, Encyclopædia Britannica, Inc. announced a partnership with mobile phone development company Concentric Sky to launch a series of iPhone products aimed at the K-12 market. On 20 July 2011, Encyclopædia Britannica, Inc. announced that Concentric Sky had ported the Britannica Kids product line to Intel's Intel Atom-based Netbooks and on 26 October 2011 that it had launched its encyclopedia as an iPad app. In 2010, Britannica released Britannica ImageQuest, a database of images. In March 2012, it was announced that the company would cease printing the encyclopaedia set, and that it would focus more on its online version. On