Numismatics

Numismatics is the study of coins. Coins yield information on the condition of country. The coins made of gold, silver and copper speak of the economic situation of that place in the period. Coins gives us chronological information. It also  gives us knowledge about the extent of influence of that a particular ruler or kingdom and its relation with the distant areas. Roman coins discovered in India gives us an idea about the existence of contacts with the Roman empire. Coins are the only source of idea knowledge of the Bactarian; Indo-Greeks and Indo-Parthian dynasty. The coins of this period brings to light an improvement in the coin artistry of India. Portraits and figures, Hellenistic  art and dates on the coins of the western straps of Saurashtra are remarkable sources for reconstructing this period. The Puranic accounts of the Satavahanas is ascertained from the Jogalthambi hoard of coins.
The circulation of coins in gold and silver during the Gupta empire imparts an idea of  the healthy economic condition during the rule of the Guptas.
. Typical Indus inscriptions are no more than four or five characters in length, most of which (aside from the Dholavira "signboard") are exquisitely tiny; the longest on a single surface, which is less than 1 inch (2.54 cm) square, is 17 signs long; the longest on any object (found on three different faces of a mass-produced object) has a length of 26 symbols.

While the Indus Valley Civilization is generally characterized as a literate society on the evidence of these inscriptions, this description has been challenged on linguistic and archaeological grounds: it has been pointed out that the brevity of the inscriptions is unparalleled in any known premodern literate society. Based partly on this evidence, a controversial paper by Farmer, Sproat, and Witzel (2004)[46]argues that the Indus system did not encode language, but was instead similar to a variety of non-linguistic sign systems used extensively in the Near East...