1 98 



NATURE 



{Jime 20, 1878 



Dr. Klein's new crater be confirmed, it will form the 

 strongest possible evidence of a real change on the 

 surface of the moon, a change, moreover, of a volcanic 

 nature. 



The I>I.;rc '''nporum in which the new crater is situated 

 lifes close to the centre of the visible surface of the moon, 

 '■So that objects in this region are very slightly affected by 

 "the lunar librations. Fortunately it is a portion of the 

 surface which has been most carefully studied by Lohr- 

 mann, Madler, Schmidt, and Neison ; for had this new 

 crater of Dr. Klein appeared in a less well-known region, 

 much doubt would have been felt as to whether it had 

 previously existed or not. 



DEEP-SEA DREDGING OFF THE GULF OF 

 MEXICO 



'X'HE last number of the Bulletin of the Museum of 

 -*• Comparative Zoology at Harvard College, Cam- 

 bridge, Mass., contains a letter from Alex. Agassiz to the 

 superintendent of the United States Coast Survey, detailing 

 the results of some recent dredging operations in the United 

 States schooner Blake. A series of deep-sea dredgings 

 were made in the first place across the Florida Channel 

 from Havana to Sand Key, out to the Tortugas reefs, 

 then across the Gulf to the Yucatan Bank, to Vera Cruz, 

 about the Alacran reef and then across the Yucatan 

 Channel, and in the trough of the Gulf Stream to Sand 

 Key, Florida — in all about 1,100 miles of lines taking 

 the shortest distance from point to point. The results of 

 the cruise are full of interest; we can only allude to 

 a few of them. The great Alacran reef is an atol — an 

 atol existing not as Darwin suggests to be the case with 

 atols in general, in an area of depression, but in one of 

 elevation, like those in which the Florida and Bahamas 

 reefs are found. The formation of the Alacran reef is in 

 full activity, the eastern slope is nearly perpendicular, 

 rising to a height of twenty fathoms from the surface in 

 a comparatively short distance. It is exposed to the full 

 force of the north-east trades and the surf breaks heavily 

 against the great masses of Madrepora palmaia,yi\v\ch. 

 build up the narrow line of coral barely flush with the 

 level of the sea. The western slope is much more gentle, 

 and here the reef consists of a number of half -made 

 narrow islands. These are mere strips of sand formed 

 by the breaking-up of the exposed masses of coral, which 

 are gradually cemented together by the accumulation of 

 the loose material held in suspension by the water. 

 Here, in the shallower parts, grow huge masses of 

 Astrsea, of Gorgoniae, of Meeandrina, which now and then 

 rise to the surface. 



Along the Cuban coast the dredge brought up immense 

 numbers of siliceous sponges, a species of Favosites, 

 which we are tantali singly told is perhaps the most 

 interesting coral ever dredged. We presume it was found 

 living, and we all know that this genus was founded by 

 Lamarck for some fossil corals, only found in the very 

 oldest strata (Silurian and Devonian), a young Holopus 

 in excellent condition (probably the fourth or fifth speci- 

 men ever found). The dredge worked well to a depth of 

 upwards of 2,000 fathoms. One haul in 860 fathoms 

 brought up an unusually large number of two and one 

 valved mollusca, including many of exquisite beauty. 

 Some most gorgeously coloured Crustacea were brought 

 up from a depth of 1,920 fathoms, and what are We to say 

 to an isopod allied to Aega, and upwards of eleven inches 

 in length and three in width ? Amongst the strange fish, 

 we read of one like a huge tadpole with a gigantic round 

 cartilaginous head, and without eyes ; of another with a 

 drawn-out flat head, very little eyes, but possessed of 

 gigantic filaments, as long as the whole body, and 

 extendmg from the tips of the pectoral and lower caudal 

 fins. Some of the Holothurians were striped with bands 

 of a deep crimson colour. 



Certainly the wonders of the deep-sea are not yet 

 exhausted, and though the treasures found by our own 

 Challenger expedition were great, it could reap the 

 produce of but a very narrow belt out of the gieat 

 expanse of the ocean world. 



A steel wire rope was used by Capt. Sigsbee. The time 

 required to reel in was always below one minute per 100 

 fathoms, sometimes not more than twenty seconds, while 

 the time required to strike bottom averaged thirty-five to. 

 forty-five seconds per 100 fathoms in the deepest sound- 

 ings of 2,000 fathoms. The wire rope was of galvanised 

 steel with a hemp coil ; it measured i| inch in circum- 

 ference, and weighed i lb. to the fathom, and had a break- 

 ing strain of over 8,600 lbs., and its own weight made the 

 use of heavy weights to sink it unnecessary. 



The Blake is now on a cruise to explore the inner por- 

 tions of the Gulf of Mexico, commencing with a run from 

 the Tortugas to the mouth of the Mississippi River, irk 

 which we wish her crew of all ranks every success. 



E. Perceval Wright 



METEOROLOGICAL NOTES 



Mr. Ellis has made a valuable contribution to the 

 diurnal variation of the barometer in a paper published in 

 they^«r«rt/of the Meteorological Society of London, which 

 gives the hourly variations from the means of each month 

 as deduced from a discussion of the photographic records 

 taken at the Royal Observatory during the twenty years 

 ending 1873. The forenoon maximum occurs from May to 

 July about 9 AM., being fully an hour later than at Kew. 

 The morning minimum at the same season becomes less 

 marked than at other times of the year, as happens irk 

 situations more or less continental in middle and higher 

 latitudes ; and this feature of the diurnal variation is, it 

 may be remarked, decidedly better marked at Kew than at 

 Greenwich. Mr. Ellis gives, for comparison with Green- 

 wich, the curves for Oxford, Washington, Cape of Good 

 Hope, and Ascension, from which he draws the broad con- 

 clusion that in high latitudes the forenoon maximum occurs 

 earlier when the sun rises early, it being however omitted 

 to be pointed out that this holds good only in situations 

 more or less continental or removed from the more imme- 

 diate influence of the sea. Thus the forenoon maxi- 

 mum which occurs at Greenwich at 9 a.m. and at Kew at 

 8 A.M,, is delayed at Falmouth and Valentia to about 

 1 1 A.M. or noon ; whilst at Helder the time of its occur- 

 rence in June is about 2 P.M. The hourly barometric 

 values for the twenty years were arranged with reference 

 to the time of the moon's meridian passage with the result 

 that no certain indication of lunar variation was apparent. 

 We hope that by-and-by the main details of this elaborate 

 discussion will be printed ; such details as will embrace, 

 at least, the hourly values of each day and month of the 

 twenty years for the examination of many inquiries re- 

 ferring to both civil and lunar days, which are now rising 

 into questions of the highest importance. 



Prof. Loomis has recently examined all the cases 

 of violent winds of the United States which have 

 been recorded as having occurred from September, 

 1872, to May, 1874, the number of cases on which 

 the wind rose to or exceeded forty miles an hour being 

 250. During the six months from November to April,, 

 violent winds were more than five times as frequent as 

 during the other six months of the year. The great 

 preponderance of violent winds are from the north ; thus 

 from north-east, north, and north-west, the number were 

 143, whereas from south-east, south, and south-west, there 

 were only 58. Generally speaking, violent winds increase 

 in frequency and intensity over North America with lati- 

 tude. Local conditions exercise a considerable influence 

 on the force of the wind. Thus violent winds are of most 

 frequent occurrence near the Gulf of St. Lawrence and 

 the Great Lakes, particularly Lakes Michigan and Erie. 



