PREFACE. 



the Speaking Trumpet. 9. Improvement in Woulfe's Ap- 

 paratus. 10. Method of drawing a Line in a Circle equal 

 to the Side of its Square. 11. Two quarto Plates, exhibit- 

 ing highly magnified Representations of the Parasitic Plant 

 which causes the Blight in Corn, from Drawings by M 

 Bauer, Botanical Painter to the King. 12. Mathematical 

 Diagrams of the Properties of Triangles, by Mr. Gough. 

 13. Application of Spectacle Glasses, by Mr. E. Walker. 



Soho Square, April, T80i5>. 



