November 15, 1S94] 



NA TURE 



61 



50, 100, or 200 diameters. The inks of commerce vary 

 somewhat in composition, hence the facihty with which 

 certain crystalline forms are obtained difters. All inks, 

 however, having a base of solution of gall-nuts and sul- 

 phate of iron, give analogous results. 



Dr. Trouessart hesitates to express an opinion as to 

 the nature of the salt which crystallises in the forms 

 illustrated. The crystals chiefly belong to the cubical 

 system, and this suggests that they are magnetic oxide 

 of iron. On the other hand, their white colour, and the 

 peculiar shapes of some of the groups of crystals, indicate 

 that iron disulphide or marcasite is the substance in ques- 

 tion. Perhaps some worker in chemical crystallography 

 will determine the point. 



NOTES. 



We learn from the Lancet that the late Prof. Pouchet, of the 

 Museum d'Histoire Naturelle, has bequeathed his entire fortune 

 to the Paris Society of Biology. The bequest is made in the 

 following terms: "N'ayant pas de famille, je legue tout ce 

 que je possede a la Societe de Biologie, oil j'ai toujour^ trouve 

 bon accueil et sympathie depuis le jour oii j'en ai ele membre. 

 Je crois fermement que c'est le meilleur usage social a faire du 

 peu de bien que je laisse environ 2000 francs de rente." (^80 

 a year). 



Dr. Walter Dickson, R.N., the author of "The Ant- 

 arctic Voyage of H.M.S. Pa^oJa," and several works on naval 

 hygiene, died on the 9th inst. at the age of seventy-three. 



By the recent death of Lieut. -Colonel Garrick Mallery, in his 

 sixty-fourth year, the U. S. Bureau of Ethnology has lost one of 

 its chief ornaments. The results of his important researches into 

 the sign and gesture language of American aborigines occur in 

 the current annual report of the Bureau. 



The Times reports a severe earthquake and volcanic eruption 

 at Ambrym, an island in the New Hebrides group. The dis- 

 turbance is said to have occurred on October 15, when several 

 severe shocks were felt throughout the whole island. Immedi- 

 ately afterwards the volcano, which is 2500 feet high, was 

 observed to be in active eruption. The lava destroyed the 

 native villages on one side of the island, and a large number of 

 natives sought refuge on board H.M.S. Dart, which was 

 cruising off the coast. Considerable damage appears to have 

 been done in a large portion of the island. 



The Christmas course of lectures, adapted to children, at the 

 Royal Institution, will be delivered by Prof. J. A. Fleming, 

 F.R. S. The subject will be "The Work of an Electric 

 Current," and the first lecture will be delivered on Thursday, 

 December 27, at three o'clock. 



For several weeks the weather over the British Isles has been 

 very unsettled, but no gales of serious importance had been 

 generally experienced until Sunday night, when a deep baro- 

 metric depression reached our south-west coasts from the Atlantic, 

 accompanied with very heavy rainfall in the south and west ; 

 'he amount measured at Scilly during twenty-four hours ending 

 8 a.m. on the 12th instant amounted to over three inches, or 

 nearly the average fall for the month, while at Hurst Castle, on 

 the Hampshire coast, the fall exceeded two inches. The central 

 area of the storm passed the whole length of the English 

 Channel, and crossed the North Sea during Monday night, 

 Strong northerly gales being experienced in the rear of the dis- 

 turbance, accompanied with thunderstorms, hail, and more 

 NO. 1307, VOL. 5 l] 



heavy rain, the amount measured in London on the 13th 

 instant being about 075 inch. A very rough sea was experienced 

 in the English Channel and in the Irish Sea. This disturbance 

 was followed by another which approached our extreme north-west 

 coasts on Tuesday night, causing strong gales overall parts of the 

 country, and very heavy rain in the west. The temperature 

 has been from 4° to 6" above the mean ; during the week ended 

 the nth instant the highest maxima recorded were 61° in the 

 Channel Islands, and 60° in the south of England, and the 

 lowest minima fell to 29° in the south-west of England, and to 

 32° in the Midland Counties. 



Prof. Guido Cora, of Turin, will, on his approaching 

 birthday, December 20, be presented by his former students 

 with "a special mark of esteem and affection" in the form of a 

 memorial in recognition of the twenty-fifth anniversary of his 

 first published paper. It is well known that he founded and has 

 maintained the geographical Journal, Cosmos, at his own expense. 

 In order to give his many scientific friends an opportunity of 

 sharing in the general recognition of Prof. Cora's labours, Prof. 

 Paul Revelli, 12 Via Galliari, Turin, is prepared to receive any 

 written "sentiment," portrait, drawing, or signature for the 

 memorial volume. The date up to which such tokens of respect 

 may be sent is extended to March 31, 1895. 



Dr. Do.naldson Smith, who left London early this summer 

 to attempt to reach Lake Rudolf from the north-east, has been 

 able to send letters home from a position in 7° 11' N., and 

 42° n' E., dated early in September. He hid formed a 

 caravan at Berbera, started with more than a .hundred 

 camels, and travelled south-westward through an unmapped 

 country, of which lie has made a running survey. At Turfa he 

 reached a great river, which he believes to be the Erer, and to 

 be continuous with the Webi Shebell. Being unable to cross, 

 he spent a week in following the course of this river, thirty miles 

 of which he has mapped ; and on his return he succeeded in 

 finding a ford, where the caravan crossed with much difiiculty. 

 The country was very thinly peopled, on account of wars between 

 the Gallas and Ogadams, but some natives were found to carry 

 letters to the coast, a task which they must have performed very 

 expeditiously. Dr. Smith has made large collections of the 

 fauna and flora of the region traversed, and has had some thrill- 

 ing adventures with big game. His men were doing well, and 

 he was confident of success in his journey, although the time 

 necessary to complete it appeared likely to be rather longer 

 than was originally expected. 



The death is announced of Colonel R. \'. .Vrmstrong, C.B., 

 F.R.S., late of the Royal Engineers. He was born in 1839, 

 and was the son of the late Rev. W. Armstrong, of Cairy, 

 County Sligo. 



In the last number of the Scottish Geographical Magazine 

 Mr. W. S. Anderson, of the Scottish Marine Station, discusses 

 the relative merits of the methods for determining the density o f 

 sea-water by means of hydrometers and by direct weighing. He 

 shows that if the temperatures of water, instrument, and air are in 

 equilibrium, and the observations made on land, the Chalicnger- 

 type hydrometer yields results of equal value with those of 

 Sprengel tubes, provided the mean of a large number of ob- 

 servations is taken. At sea the hydrometer is less satisfactory. 

 Mr. Anderson throws discredit on previous work in this 

 direction, and assumes that the work of some earlier observers 

 showed large discrepancies on account of the scale of the 

 hydrometer being read from the wrong end. Unfortunately, he 

 does not make any reference to the place where this work is 

 published. By the use of a very large hydrometer admitting of 



