This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1810 Excerpt: ...by the converse operation. These tables have been copied from the second edition of this work, printed in 1 01, into an Epitome of Navigation, printed in l os, without mentioning from whom they took it, and strange to tell, the compiler of that book says, in his explanation of the Tables, " they were formerly comprised in one table, but it has been thought more convenient to separate them, which we have accordingly done." Example. Examples. I. Required the log. rising answering to 6h. 24' 53"? Log. rising of 6h. 24' 50'-5.0445g-6 25 0-5.04487 Difference 28 Now 28 X3"-84, then the right hand figure 4, being pointed off, and the remainder 8, added to 5.04459, gives 5.04467, the log. rising answering to 6h. 24' 53." II. Required the time answering to log. middle time 4.92799? Given log. middle time--4.Q2799 Next preceding log. being that of Ih. 40' 10" 4.92766 Difference.... 33 Now, a cypher being annexed to 33 makes 330, which divided by 68, the difference between the logs, of Ih. 40' 10" and 'h. 4O' 20," the quotient is 5" nearly, which added to Ih. 40' 10" gives Ih. 40' 15," the time required. Remark. Table Xlvih. orthat of half elapsed time, is the logarithmic cosecant of the corresponding time expressed in degrees. Table Xlix. is the sum of the log. sine of the given arch, and 0,301o3, the index being diminished by 5; and Table L. is the log. versed sine of the corresponding arch, reduced to degrees. TABLE LI. Proportional Logarithms. This table was calculated by Dr. Maskelyne, in order to render the operation more easy for finding the apparent time at Greenwich, answering to a given distance between the Moon and the Sun, or a fixed star. It is extended to three hours, on account of th...