1S6 Oil iJie Naulical Almanac. 



Thus may be seen that the extent of modern attainment Is 

 only an approximation towards arithmetical progression ; and if 

 the l)asis of our system (for such I consider the connnon chords) 

 can lav no higher claim to perfection, then must our harmony 

 be very low indeed. Harmanic proportion requires, that of four 

 immhers, the first number shall bear the same ratio to the fourth, 

 which the difference between the first and second number shall 

 bear to tlie difference between the third and fourth. If harmony, 

 then, in the true sense of the word, be at all attainable, let u« 

 judiciously subdivide the scale for the purpose : but, on the con- 

 trary, if it be wholly ?iwattainable, let us discontinue the tor- 

 turing of nature by the perpetual violation of her proportions. 

 [To be continued.] 



XXXI. Oh the Nautical Jlmanac. 

 To Mr. Tilloch. 



^la, —In the last number of your valuable Magazine (p. 146) 

 a correspondent, under the assumed title of Manchestriensis 

 has thought fit to reply to the observations which I lately made 

 on the gross and numerous errors in the Nautical Almanac: and 

 he is pleased to say, with no small degree of pride and satisfac- 

 tion, that he is able to refute and contradict my assertions "with 

 the utmost confidence." Notwithstanding the modest tone of 

 this sentence, and the magisterial air which the writer assumes, I 

 can only state in reply that, as to the occultation of Mars on 

 Jan. 1, 1S20, I have carefully revised mv calculations on that 

 subject, and still find (in spite of what Manchestriensis may 

 say) that there will be an occultation on that day : and in this, 

 I am partly borne out by the Comiaissance des Terns, which states 

 that it will be visible also at Paris. The longitude and height of 

 the Nonagesimal, and the quantity of the Parallax both in lon- 

 gitude and latitude, I have deduced, not from any tables but, from 

 a trigonometrical calculation, on the assumption that the sphe- 

 roidal figure of the earth is 299 : 300. 



I have had recourse likewise to the same method, for deter- 

 mining the time of the commencement of the great solar eclipse 

 on Sept. 7, 1820 : which (if there be any truth in the formulae 

 given by all the writers on this subject) will certainly commence 

 at Greenwich at 0*^ 23*' 10"; and the moon will make the first 

 impression on the sun's disc at 48'^ 22' from the vertex. If there- 

 fore these values differ from those given by Manchestriensis, 

 it must arise from our having made use of different methods: but 

 I am at a loss to account for the bold assertion which he has 

 made that it is not of any consequence whatever to notice the 



point 



