WHAT TO USE FOR WATER-PIPES. 145 



jectionable feature of rust is to coat the interior 

 with hydraulic cement. The Melrose and Maiden 

 Aqueduct Co., who have just introduced the waters 

 of Spot Pond into those towns, are using a cement- 

 lined iron service-pipe, and we predict for it entire 

 success. It is cheap and durable, and oxidation 

 is wholly prevented by this device. Large pipes 

 are now successfully constructed of cement, with 

 a thin iron pipe upon which it rests, interiorly and 

 exteriorly. Pipes of this kind which have been 

 several years in use, continue, we believe, to afford 

 the highest satisfaction. 



GUTTA-PERCHA PIPE. 



In seeking for a satisfactory material for water- 

 pipes, the curious vegetable substance, gutta-percha, 

 has been used to some extent. All metallic con- 

 tamination is at once entirely avoided by the em- 

 ployment of this material, and apparently it has 

 much to recommend it to favor ; but, like a thou- 

 sand other good things, it has objectionable fea- 

 tures. Gutta-percha imparts to water in contact 

 with it an unpleasant taste, and also, in some local- 

 ities, it undergoes a kind of spontaneous decompo- 

 sition, by which it is rendered worthless. If, how- 

 ever, these objections did not exist, we presume 

 the item of cost would come in to drive it in a 

 great degree from the market. At the present 

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