[Pramāṇa](https://indike.org/pramana/) › [Studies](https://indike.org/pramana/ins) › [Science, technology and education](https://indike.org/pramana/ins.science) › [Yantras or Mechanical Contrivances in Ancient India](https://indike.org/pramana/ins.science.raghavan-1952) › c2.88 # Yantras or Mechanical Contrivances in Ancient India c2.88 Yantras or Mechanical Contrivances in Ancient India c2.88 - **Language:** English ### [c2.88](https://indike.org/pramana/ins.science.raghavan-1952.c2.88) Towards the end of the 7th century the architect Kallinikos of Heliopolis, when Constantinople was besieged by Arabs in 668, manufactured big tubes made of iron or of other metals formed like big beasts with gaping jaws, out of which were thrown iron, stones and combustibles. In consequence of the havoc caused by these projectiles the siege of the city was raised. The Greeks kept, it is said, the composition for four centuries when it was betrayed to the Saracens, who availed themselves of it during the crusades at Jerusalem and also at Damietta. (Oppert p. 47) - [Previous: c2.87](https://indike.org/pramana/ins.science.raghavan-1952.c2.87) - [Next: c2.89](https://indike.org/pramana/ins.science.raghavan-1952.c2.89) - [Up: c2](https://indike.org/pramana/ins.science.raghavan-1952.c2) --- Source: [https://indike.org/pramana/ins.science.raghavan-1952.c2.88](https://indike.org/pramana/ins.science.raghavan-1952.c2.88) · Pramāṇa