ri PREFACE. 



" The Actual Costs and Capacity of Recently Erected Gas- 

 works," which forms an excellent supplement. And thanks 

 are due to Mr. J. \V. Frost, accountant to the Salisbury 

 Gas Company, for assistance in connection with Chapter 

 XIV'., :md in the preparation of the forms and tables. 



N. H. HUMPHRYS. 

 Salisbury, July 1911. 



