2. Pietro Antonio Cataldi (mathematician born 1552 ad, died 1626 ). 1602 ad –Cataldi discovered sixth and seveth perfect numbers, 2 16 (2 17 – 1 )= 8589869056 and 2 18 (2 19 - 1 ) = 137438691328. Perfect number is a positive integer that is equal to the sum of its proper positive divisors.

3. Willebrord Snell (mathematician born 1580 ad, died 1626 ). 1606 ad – Snell take the first attempts to measure the meridian arc of the Earth s surface, in connection with that determines her height. PublishesMathemathic Memorandum.

4. Claude-Gaspard Bachet de Méziriac (mathematician born 1580 ad, died 1626 ). 1612 ad – Bachet publishes his work abouth mathematical puzzles and tricks, which will be the basis for almost all later books concerning mathematical entertainments.

5. Pietro Antonio Cataldi describes the square roots using periodic fractions.

6. John Napier - (mathematician born 1550 ad, died 1617). 1614 ad –First publishes his work about logarithms „Miriffci logarithmorum cannonis descriptio”

7. Willebrord Snell describes the trigonometric triangulation technique, which contributes to making accurate cartographic measurements

8. Paul Guldin (mathematician born 1577 ad, died 1643). 1620 ad –Guldi n formulates theorem about center of gravity.

9. Henry Briggs (mathematician born 1561 ad, died 1630). 1624 ad –Briggs published work „ Arithmetica Logarithmica” that gives the logarithms of natural numbers from 1 to 20 000 and 90 000 to 100 00.