Hermann Hankel (1839 - 1873)

**KALKI** · #1 08-02-2015

Hermann Hankel (14 February 1839 – 29 August 1873) was a German mathematician who was born in Halle, Germany and died in Schramberg (near Tübingen), Imperial Germany.

He studied and worked with, among others, Möbius, Riemann, Weierstrass and Kronecker.

His 1867 exposition on complex numbers and quaternions is particularly memorable. For example, Fischbein notes that he solved the problem of products of negative numbers by proving the following theorem: "The only multiplication in R which may be considered as an extension of the usual multiplication in R+ by respecting the law of distributivity to the left and the right is that which conforms to the rule of signs." Furthermore, Hankel draws attention to the linear algebra that Hermann Grassmann had developed in his Extension Theory in two publications. This attention was the first of many notations later made to Grassmann's early insights on the nature of space.

**KALKI** · 08-02-2015

Hermann Hankel (1839 - 1873) born in Halle, Germany in his History of Mathematics says:

“ It is remarkable to what extent Indian Mathematics enters into the Science of our time”

(source: Is India Civilized? - Essays on Indian Culture - By Sir John Woodroffe Ganesh & Co. Publishers 1922 p. 182).

The earliest recorded Indian mathematics was found along the banks of the Indus. Archaeologists have uncovered several scales, instruments, and other measuring devices. The Harappans employed a variety of plumb bobs that reveal a system of weights 27.584 grams. If we assign that a value of 1, other weights scale in at .05, .1, .2, .5, 2, 5, 10, 20, 50, 100, 200 and 500. These weights have been found in sites that span a five-thousand-year period, with little change in size.

Archaeologists also found a “ruler” made of shell lines drawn 6.7 millimeters apart with a high degree of accuracy. Two of the lines are distinguished by circles and are separated by 33.5 millimeters, or 1.32 inches. This distance is the so-called Indus inch.

(source: Lost Discoveries - Dick Teresi p. 59).