抄録
The auther contrived the following nomograms to find the ship's position concerning astronomical and geographical navigation without resorting to complicated numerical calculations. His intention was to simplify the calculations by operating a special ruler on those nomograms. The book contains 93 sheets of nomagrams or alignment charts and 11 sheets of ordinary tables. The principal nomograms are as follows: - [table] The auther believes that these nomograms will fulfil the purpose of practical navigation, in view of their accuracy as well as simplicity.
