485 



bhe paste, or mortar, to ensure a close and compact bond with 

 those -which surround it. 



lit this condition the material is put, layer after layer, into 

 moulds of the necessary size and d 'sign-, and thoroughly rammed at 

 each stage of the process. The sides of the mould arc then removed 

 and the material allowed to harden. After a few days it may he 

 removed for use, if handled carefully, hut experience indicates that 

 the Beton reaches its best condition in proportion to the time it is 

 permitted to remain, under favorable circumstances, in an equable 

 atmosphere, so that it may attain a certain state of "case harden- 

 ing," by absorption of carbonic acid. It is claimed by the con- 

 t ractors to be impervious to water, and this may bo the result, for 

 all practical purposes, in cases where it has become thoroughly 

 indurated, but it can be so only in proportion as the induration pro- 

 ceeds from time and favorable exposure. 



From tests made on the Park, it was found that a block of this 

 material, several months old, absorbed 50 per cent more water than 

 Ohio sandstone of the same dimensions, under similar conditions. A 

 block of Beton of more recent manufacture would absorb an in- 

 creased volume of water, and the reverse would be the case with a 

 block of greater age and longer exposure. 



The material is certainly susceptible of strength and hardness, as 

 claimed, and if its components are of proper excellence of th 

 kinds, and adjusted with discretion, there can be little doubt of its 

 ability to maintain the general reputation claimed for it as to dura- 

 bility. The effect of the action of the atmosphere, in our variable 

 climate, upon the surfaces of ornamental work, is yet to be expe- 

 rienced. 



A rustic bridge, of locust, with stone abutments, has been built 

 over an arm of the lake, near its south easterly corner. It is 83 

 et above the summer level of the lake, and carries 

 a 1G foot walk, running southerly from the carriage concour- 



A small rustic bridge, in cedar, has been built, carrying 

 Westdale walk over the brook, which serves as an outlet to the 

 upper pool. A temporary bridge, 140 feet long arid 30 feet wide, 

 has been built to accommodate travel during the progress of con- 

 struction of Cleft riuge span. 



BUILDINGS AND STRUCTURES. 



The concert grove house was let by contract, under the direction 

 of the Executive Committee of the Board, to Messrs. Osborn & 

 Fish, of Brooklyn, in May last, and is now nearly completed. This 



