Cipher

All ciphers involve either transposition or substitution, or a combination of these two mathematical operations—i.e., product ciphers. In transposition cipher systems, elements of the plaintext

Hanafiyah

Also called  Madhhab Hanifah , English  Hanafites  in Islam, one of the four Sunni schools of religious law, incorporating the legal opinions of the ancient Iraqi schools of al-Kufah and Basra. Hanafi legal thought (madhhab) developed from the teachings of the theologian Imam Abu Hanifah (c. 700–767) by such disciples as Abu Yusuf (d. 798) and Muhammad ash-Shaybani (749/750–805) and became the official system of Islamic legal interpretation of the 'Abbasids, Seljuqs

Brahmaputra River, Plant and animal life

The most notable

Furniture, Mirrors

The use of mirror glass in furnishings arose during the 17th century. The discoloration of the melted glass because of silvering and, not least, the prohibitive cost and difficulty of manufacturing mirror glass of considerable size restricted the possibilities of large-scale application. The mirror gallery at Versailles was thus an outstanding technical achievement

Potassium-argon Dating

Method of determining the time of origin of rocks by measuring the ratio of radioactive argon to radioactive potassium in the rock. This dating method is based upon the decay of radioactive potassium-40 to radioactive argon-40 in minerals and rocks; potassium-40 also decays to calcium-40. Thus, the ratio of argon-40 and potassium-40 and radiogenic calcium-40 to potassium-40 in a mineral

Arabia, History Of, The Zaydis and 'Alawis

In the mid-10th century a refugee from disturbances in Iraq, Ahmad

Cavalcanti, Guido

Born into an influential Florentine family of the Guelf (papal) party, Cavalcanti studied under the philosopher and scholar