تاریخ علم

It is known that contaminated water contains many bacteria and harmful viruses that cause many diseases such as typhoid, cholera, dysentery, meningitis and poliomyelitis, etc. Water-related diseases are the most critical health problems in the world now, therefore the mechanisms of sterilize water and its development gained the attention of governments and scientists. This attention makes many people believe that water sterilization technology is a modern technology. Perhaps the reason for this belief is that ancient people were not able to see those microorganisms. In this research, we have found that ancient scholars realized the existence of these objects and tried to get rid of them in several ways. Some of these ways were successful, and could be considered as a basis for modern techniques.    Polluted water passes through several stages of processing to become pure clear drinkable water. In this research, we will mention a summary of each procession stage (sedimentation-filtration-sterilization), then we will refer to the history of the evolution of this stage in various ancient civilizations, and finally we will explain it in Arab civilization.

Jām-e gītī-namā is a late instrument for determining qibla introduced in a treatise by Muḥammad Riḍā Yazdī (fl. Yazd, ca. 1867) entitled On Finding Qibla and Some Other Instruments. The author wrote it to investigate some earlier scientific instruments found at that time including a qibla-indicator. Although he did not describe the instrument in detail, his method of expressing its function leads us to consider it as a Mecca-centered world-map for finding the direction and distance to Mecca. As he found it impossible to determine the direction to Mecca through projecting, he devised jām-e gītī-namā to use its numerical results regardless of its spherical representation. This paper examines Muḥammad Riḍā’s approach on devising a new instrument for determining qibla inspired by an old one, in order to shed more light on qibla-indicators, more especially, Mecca-centered world-maps.