■45S Notices respecting New Books. 



John Harrison Curtis, esq. Aurist to His Royal Highness the 

 Prince Regent, and Surgeon to the Royal Dispensary for the 

 Diseases vfthe Ear, is about to pubhsh A Treatise on the Phy- 

 siology and Diseases of the Ear, containing a comparative View 

 of its Structure and Functions — and of its various Disea^>es. This 

 Work is intended chiefly for deaf persons, and will be acconipa- 

 Bied with an interesting Copper-plate, represoiting an invention 

 of an Artificial Ear, made in France, and which very much in- 

 creases the collection of Sound; but Mr. Curtis has made consi- 

 derable improvement in this invention, which occasions the sound 

 to enter with double force, by its being applied over the natural 

 Ear. 



Mr. Thomas Forster has in the press, and will shortly publish, 

 A Monograph of the genus Hirundo, which will contain a col- 

 lection of the evidence hitherto collected for and against the ques- 

 tiot) of tlie migration of the swallow tribe ; with numerous anec- 

 dotes. It will be illustrated by figures of the four British species. 



I am happy in being able at length to announce the speedy 

 publication of the First Part of the very useful Set of Arithmetical 

 Tables, by Henry Goodwyn, esq. which were first introduced ta 

 the notice of ujy readers, in a communication from his friend 

 Mr. Farey sen.*, inserted p. 385 of the xlviith volume. Every 

 one used to calculations must have experienced the labour at- 

 tending the reduction of vulgar fractions to their equivalent de- 

 cimal fractions, although the denominators may be small, as 

 under 100, if mam/ places of figures are wanted ; and the dan- 

 ger there is of making mistakes in such cases. And few persons 

 arc much versed in figures, without having very frequently seen 

 the still greater labour and difficulties attending the reverse of 

 the above process; viz. the reducing of a decimal fraction to its 

 equivalent vulgar fraction, when such be correctly practicable, 

 or otherwise, of finding the nearest vulgar fraction thereto ex- 



* I beg Iiere, to correct an inarciiracy and ovor-siglit which occurred 

 last month, in tlic hasty and very compressed ahstract which, for want of 

 room, I was oblii;ed t(» give in p. O-I.'i, of the Labours of the jNIathematicai 

 Class of the Institute of France; wherein the name of Mr. Farey follows 

 that of M. LapJMce, by niisfake, instead of the name of M, Cauclty, whom 

 the Secretary to tlie Jpstitutc mentions, as having given a general demon- 

 stration of the curious property of vii!i;ar Fractions, which Mr. Farcy had 

 ptiblished in tiie Philosophicai Magazine. Mr. Farcy's late Communication 

 to me on the subject, wiiich { have given in a Note in tfie page quoted, 

 correctly refers to what had appeared in ih\i ^^ Analyse dcs Travaux," fic. 

 with respect to liimself, and tlie error mentioned, lay entirely with me:— 

 Jm line 7 from the butlum of the iSolc referred to, for any, read my. — 

 JiDirott. 



pressed 



