Notices respecting New Books, 69 



and to explain the waj's of measuring the principal dimensions of 

 the solar and sidereal systems." — P. iv. 



The lectures were given on six successive nights, from March 13 

 to March 18, 1848, at the Temperance Hall, Ipswich, to between 

 600 and 700 hearers, a large proportion of whom were working men. 

 Shorthand-writers were engaged to take down the lectures ; and the 

 fair copy, revised and corrected by the author, forms the present work. 

 As might be expected from Mr. Airy, these lectures are quite ori- 

 ginal, and very dissimilar from the greater part of treatises professing 

 to be popular. He has carefully avoided the introduction of theo- 

 rems unknown to the majority of his audience, and those common- 

 places which too many persons think proper food for uneducated 

 listeners. Any one who has learned to solve a plane triangle by cow- 

 struction, and a spherical triangle by the globe, and who is able to 

 give sustained attention to a chain of reasoning, will find no diffi- 

 culty in comprehending the whole book. But it must not be con- 

 sidered to be light reading. The truths of astronomy, like most 

 things worth knowing, demand considerable mental exertion for 

 their acquisition. Skill in the teacher may make the steps more 

 easy, and to some extent supply the want of preliminary training ; 

 but it would be unreasonable to expect that a science, deduced from a 

 few indisputable phaenomena by strict mathematical reasoning, can be 

 as easily mastered by a man of plain common sense as by a geometer. 

 The scope and results of astronomy, a good notion of its methods, 

 its difficulties and its triumphs, may be obtained' from this book and 

 from another volume* by the same author, even by those who have 

 not had the advantage of a mathematical education : and we are of 

 opinion, that such a course of study would not only convey a large 

 amount of sound information on an interesting subject, but would 

 be singularly well adapted to strengthen and chastise the powers 6f 

 a student irregularly and imperfectly educated. "^ 



It is indeed to persons of this class that the lectures were more 

 particularly addresed. " I wish," says the author, "to invite espe- 

 cially the attention of those who are commonly called working-men, 

 to the few lectures 1 propose to deliver. The subjects upon which I 

 have to treat are commonly regarded as rather beyond their reach ; I 

 take this opportunity of saying that the subjects of the lectures will not 

 be beyond any working-man's comprehension. Everybody who has 

 examined the history of persons concerned in the various branches 

 of science, has been enabled to learn that, whereas on the one hand 

 those who are commonly called philosophers may be as narrow- 

 minded as any other class, and as little informed ; so on the other 

 hand, those who have to gain their daily livelihood by handicraft, 

 may associate their trades or businesses, whatever they may be, with 

 accomplishments of the most perfect and the most elevated kind. I 

 think, then, it is right I should repeat, that these lectures will be 

 directed in some measure with the object of being perfectly compre- 



* Gravitation, an article in the Penny Cyclopiedia, also published in a 

 separate volume. 



