4oS 



NATURE 



[December 12, igi; 



proljlcms of modern psychology. For these 

 religions tell us exactly what has taken place in 

 the human brain during- this period of develop- 

 ment. The evolutionary process . . . has added 

 to the human brain a new layer of cells ; and it is 

 the progressive development of this new layer 

 of cells, carried on through each successive wave- 

 let, that has given rise to the astounding phen- 

 omena of human history." 



The reviewer, although familiar with recent 

 research on the cortex of the brain, has failed to 

 identify "the new layer of cells" mentioned by 

 Dr. Reichardt. It appears from his text that these 

 cells were at first "barred from contact with the 

 outside world by the pre-existing mind organ," 

 but in the Greeks it appears "the new mass of 

 cells entered into relation with the outside world," 

 giving "them that brilliant power of objective 

 ideation which still glorifies them in our eyes." 

 The author's explanation of the evolution of human 

 religions and human faculties has the merit of 

 simplicity and the unfortunate demerit of being 

 founded on imagination rather than on ascertained 

 facts. 



Michael Hcilprin and His Sons. A Biography. 



By Gustav Pollak. Pp. xvi + 540. (New York : 



Dodd, Mead and Co., 1912.) Price 3.50 dollars 



net. 

 Michael Heilprin was in many ways a remark- 

 able man. A Polish Jew, who, after a short 

 residence in Hungary, betook himself to the 

 United States, he exhibited an extraordinary 

 faculty for accumulating information. The editor 

 of his life states that he read eighteen languages 

 and his memory was stored with tens of thousands 

 of dates. In America he drifted into literary work 

 and became a writer of articles in encyclopedias 

 and journals and a frequent contributor to the 

 Nation. Of his two sons, Louis, the elder, fol- 

 lowed in the footsteps of his father, but .'\ngelo 

 was destined to achieve a wider fame. 



Born in Hungary, .^ngelo Heilprin was taken to 

 Philadelphia at the age of three years. He studied 

 for a year in London at the Royal College of 

 Science, and was much impressed by Huxley's 

 personality and tuition. At first geology claimed 

 his attention, especially invertebrate palaeontology, 

 but in later years he became a well-known traveller, 

 visiting Mexico, the Arctic, British Guiana and 

 Alaska. His greatest achievement in this line was 

 his work in Martinique, where his daring ascent 

 of Montagne Pel^e within a few days after the 

 great eruption of May, 1902, showed that in 

 addition to his eminence as a scientific investigator 

 he was a man of indomitable energy and dauntless 

 courage. He died at the early age of fifty-four, 

 having apparently overtaxed his strength by con- 

 tinual travel, writing and lecturing. 



This biography scarcely does justice to its sub- 

 ject, as there is little biographical matter and the 

 book consists mostly of long cuttings from articles 

 in encyclopaedias and journals. Angelo Heilprin had 

 an attractive personality and a fine scientific record, 

 of which we get onlv faint and distant glimpses 

 in this story of his life. 



NO. 2250, VOL. 90] 



LETTERS TO THE EDITOR. 

 [I'he Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications.] 



The Rise of Temperature Associated with the Melting 

 of Icebergs. 



In a letter to Nature published in the issue ot 

 December i, 1910, I showed by means of micro- 

 thennograms taken on a trip to Hudson's Straits that 

 an iceberg melting in salt water produces a rise of 

 temperature. The experiments were performed on 

 the Canadian Government steamship Stanley, and in- 

 dicated that when approaching ice a rise ot tempera- 

 ture occurred followed by a rapid fall of temperature 

 a quarter of a mile abeam of the berg. 



During the past summer I had an opportunity of 

 examining in detail the temperature etlects of ice- 

 bergs. The Canadian Government placed their steam- 

 ship Montcalm at my disposal for the tests, and three 

 weeks were spent through the Straits of Belle Isle. 

 Careful records were made of the temperature effects 

 of icebergs and land. These tests have shown con- 

 clusively that it is the rise of temperature which is 

 the direct action of the melting iceberg, and that 

 when a fall of temperature is observed near ice it is 

 due to the influence of a colder current from the north 

 in which the iceberg is carried. The cooling influence 

 of the ice itself is very small. Cooler currents exist 

 in the main. Arctic current, whether accompanied by 

 ice or not, but the presence of the ice causes a zone 

 of water of higher temperature to accumulate for a 

 considerable distance about it. 



The icebergs I studied in the Straits of Belle Isle 

 and off the eastern end of the Straits in the Labrador 

 current showed no cooling effect even within a few 

 yards of them. 



In Fig. I 1 show the isothermal lines about a 

 typical berg off the eastern end of the Straits of Belle 

 Isle. This diagram was obtained by arranging a 

 number of courses for the ship from all sides up to 

 the ice along radii of six miles. 



As a good example of how icebergs and groups of 

 icebergs affect the water temperature, I show a 

 microthermogram in Fig. 2 taken from the records 

 which were obtained in a westward passage through 

 the Straits of Belle Isle. In every case the approach 

 to ice caused a rise of temperature. 



The explanation of this iceberg effect which I gave 

 at my Friday evening discourse at the Royal Institu- 

 tion last May was founded on Pettersson's theory of 

 ice melting in salt water. By this theory, which can 

 easily be verified by a simple experiment, ice melting 

 in salt water produces three currents : (i) a current 

 of sea water cooled by the ice, which sinks downward 

 by gravity ; (2) a current of warm sea water moving 

 towards the ice ; (3) a current of light fresh water 

 from the ice, which rises and spreads over the surface 

 of the salt water. 



I at first thought that it was this surface current 

 of fresh water that influenced the microthcrmometer 

 in the actual sea tests. The fringe of this lighter 

 water would be warmer than the sea water on account 

 of the action of the sun and scattered radiation, which 

 is very strong at sea. The lighter water would retain 

 the heat because it could not mix readily with the 

 sea water. Near the iceberg I considered that a 

 fall of temperature would result from the cooling in- 

 fluence of the surface current of fresher water. 



My recent tests have shown, however, that an ice- 

 berg melts so slowly that no effect of the dilution can 



