834 



THE POPULAR SCIENCE MONTHLY. 



ing great crevices. At some former time 

 a large segment was cut from the base of 

 this column. Starting from one of these 

 crevices, an excavation was made, cutting a 

 mass from the base having an arc of thirty 

 feet, and making a cavity in the pillar itself 

 ten feet wide, seven feet high, and five feet 

 deep. This excavation has hitherto been 

 regarded as a deliberate attempt of the 

 miners to fell the column, but Mr. Hovey 

 thinks the work must have been done a 

 thousand years ago. 



fommereial Prodnets of Kew Caledonia. 



— M. Jules Gamier, who has spent three 

 years in New Caledonia investigating its 

 mineral resources, states that all the prin- 

 cipal vegetable productions of the tropics 

 grow well on that island, though, with the 

 exception of coifee and tobacco, they are 

 subject to periodical destruction by inva- 

 sions of grasshoppers. Cotton, moreover, 

 is liable to damage during the rainy season, 

 which, coinciding with the gathering of the 

 crop, destroys the produce. There are sev- 

 eral native oil-yielding plants, and the cul- 

 ture of the mulberry and silkworm have 

 been introduced with success. The forests 

 contain many useful timber-trees ; but the 

 most active industry is the raising of cattle, 

 in which an active export trade is carried 

 on with Australia. Of other animal prod- 

 ucts there is nothing of commercial value 

 except the fish, which are abundant and of 

 great variety. The chief source of wealth 

 in the island is, however, its metallic prod- 

 ucts. It is rich in gold, copper, and nickel, 

 the latter presenting itself in the form of a 

 magnesian hydro-silicate, called by Profes- 

 sor Dana Garnierite. The native inhabitants 

 number thirty-five thousand, and the whites 

 seventeen thousand. The recent insurrec- 

 tion will not interfere with the progress of 

 the colony. 



Professor A. Agassiz's Zoological Labo- 

 ratory. — Professor Alexander Agassiz's zo- 

 ological laboratory at Newport is admirably 

 contrived to accommodate a small number 

 of workers. It is forty-five by twenty-five 

 feet. The whole of the northern side of 

 the floor, upon which the work-tables and 

 microscope-stands are placed, is supported 

 on brick piers and arches independent of 



1 the brick walls of the building. The rest 

 of the floor is supported entirely on the out- 

 side walls and on columns on the north side. 

 This gives to the microscopic work the great 

 advantage of complete isolation from all 

 disturbance caused by persons walking over 

 the floor. The material for the laboratory 

 procurable at Newport is abundant. The 

 dredging is fair and not difficult, as the 

 depth in the immediate neighborhood does 

 not exceed twenty to thirty fathoms. The 

 pelagic fauna, however, is the most abun- 

 dant. During the course of each summer, 

 by the use of the dip-net, representatives 

 of all the more interesting marine forms can 

 be found. The laboratory stands on a point 

 at the entrance of Newport Harbor, past 

 which sweeps the body of water brought by 

 each tide into Narragansett Bay, and carry- 

 ing with it everything which the prevailing 

 southwesterly wind drives before it. New- 

 port Island and the neighboring shores form 

 the only rocky district in the long stretch 

 of sandy beaches extending southward from 

 Cape Cod — an oasis, as it were, for the 

 abundant development of marine fife along 

 its shores. 



Making Sonnd-Vibrations visible. — A 



very ingenious method of recording articu- 

 late vibrations by means of photography 

 has just been invented. The apparatus 

 (says "Galignani's Messenger") consists of 

 a steel mirror capable of oscillations on a 

 diametral axis, to the back of which is at- 

 tached a lever connecting it with the center 

 of a telephone-disk arranged with an ordi- 

 nary mouthpiece. Whenever the disk is 

 made to vibrate, the mirror oscillates with 

 it, and a beam of sunlight thrown on the 

 reflector from a heliostat describes lines of 

 light on a suitably prepared screen. If the 

 latter be movable at right angles to those 

 lines of light, and carries a collodion film, 

 the oscillation of the light is recorded on 

 the prepared surface as a more or less com- 

 plex curve having the peculiarity of the 

 sound-wave which caused each particular 

 motion. Another and simpler phoneidoscope 

 is suggested by a writer in " Nature " : it 

 may be made without the aid of any appa- 

 ratus whatever, by bending the forefinger 

 and thumb of one hand so as to form a 

 circle, and then with the other hand draw- 



