Betula utilis 19th century, Kashmiri pandits reported all of their books were written on Himalayan birch bark until Akbar introduced paper in the 16th century. The Sanskrit word for the tree is "bhûrja"—sharing a similarity with other Indo-European words that provide the origin for the common name "birch". The bark is still used for writing sacred mantras, which are placed in an amulet and worn around the neck for protection or blessing. This practice was mentioned as early as the 8th or 9th century CE, in the Lakshmi Tantra, a Pancaratra text. According to legend, the bark was also used as clothing
Northern celestial hemisphere referred to as the Northern Hemisphere. For the purpose of celestial mapping, astronomers may conceive the sky as the inside of a sphere divided into two halves by the celestial equator. The Northern Sky or Northern Hemisphere is therefore the half of the celestial sphere that is north of the celestial equator. Even if this geocentric model is the ideal projection of the terrestrial equator onto the imaginary celestial sphere, the northern and southern celestial hemispheres is not to be confused with descriptions of the terrestrial hemispheres of Earth itself. Northern celestial hemisphere The northern celestial hemisphere, also called the