August ii, 192 i] 



NATURE 



765 



mediate, in comparison with the parents, in almost 

 all details, namely, shape of leaf-pitcher and lid, 

 colouring, size and shape of flower (though the flower 

 of the hybrid is inclined to be larger and more showy 

 than the parent), and size and shape of the jjetals. 

 The intermediate relation also extends to microscopic 

 details, such as character of cells of the epidermis, 

 number of stomata, and characters of the internal 

 tissues. 



Dr. H. W. Youngken has studied the comparative 

 morphology, taxonomy, and distribution of the 

 Myricacese (bog-myrtles) of the eastern United States. 

 The author finds that the infesting organism in the 

 characteristic root-tubercles is an Actinomyces, and 

 he has also observed it in the cells of the fruit-wall ; 

 after the fall and decay of the fruit it will again make 

 its way into the soil and infect roots of other Myricas. 

 Coccus-like forms, believed to be involution forms of 

 the infesting Actinomyces, were found in the pitted 



wood-vessels, and apparently indicate the pathway- 

 taken bv the parasite in order to reach the fruit- 

 wall. 



Miss Margaret Henderson describes the results o£ 

 a comparative study of the structure and sapro- 

 phytism of the Pyrolaceae and Monotropaceae in rela- 

 tion to the Ericaceae (heaths). The author suggests- 

 that the two former families differ from the Ericaceae- 

 only in their gradually increasing saprophytism and: 

 in those characters which go hand-in-hand with this,, 

 namely, loss of green colouring matter, reduction; 

 from shrubs to herbs, reduction of leaves to scales^ 

 increase in the number of seeds, and the reduction ini 

 their size and in the number of cells of the endospernr 

 and embryo. Similar degradation changes occur ih; 

 the orchid and gentian families, and the author there- 

 fore supports the view which would regard the P%to- 

 laceae and Monotropaceae, not as distinct families^ 

 but as representing subfamilies of the Ericaceae. 



The Claude Process for Ammonia Synthesis. 



I 



N the issue of the Revue scieiitifique for May 28 

 M. Georges Claude g-ives an interesting account 

 of his process for the synthesis of ammonia, depending 

 on the use of pressures approaching 1000 atmospheres. 

 The work of compression of a gas at constant tem- 

 perature varies as the logarithm of the pressure, so 

 that if the work of compression from i to 200 atm. 

 is 2-3, that from i to 1000 atm. will be only 3, or at 

 n^ost 3-5, if the diminution of compressibility at hig^h 

 pressures is taken into account. At his'h pressures, 

 however, the percentage of ammonia in equilibrium 

 with hydrogen and nitrogen will be greatlv increased. 

 Claude announced in 1917 that his experiments indi- 

 cated that the yield could be increased from about 

 13 per cent, at 200 atm. to more than 40 per cent, 

 at 1000 atm., the temperature being the same in both 

 cases. A production of 6 grams of ammonia per 

 gram of catalyst an hour, as compared with 0-5 

 f2rrams in the Badische process, is attained. Whereas 

 it is necessary at 200 atm., employed by the Badische 

 Co., to circulate the ^as several times over the 

 catalyst, and to separate the ammonia after each 

 circulation, it is sufificient to circulate only three or 

 four times at 1000 atm. The Volume of the apparatus 

 required for the same production is onlv about one- 

 tenth that required at 200 atm. pressure. The main 

 source of difficulty in working at high pressures is 

 the evolution of heat, which is 2:^ to 50 times greater 

 than in working at 200 atm. The diflicultv is then, 

 not to conserve the heat of reaction to make the pro- 

 cess autothermic, as is the case in the Badische 

 method, but to eliminate this heat. The Claude 

 apparatus has been operated with success at La 

 Grande Paroisse with a unit producing 1-25 metric 

 tons of ammonia per day, and a larger unit, for 



5 tons per day, with a compressor Sealing with 

 700 cu. m. of gas per day, has recently been put intc^ 

 operation with success. 



The percentage of ammonia after passing- the 

 catalyst is about 25 at 1000 atm., as compared with 

 about 6 at 200 atm. The partial pressure is there- 

 fore 250 atm., as compared with about 12 atm. at 

 200 atm. total pressure. The vapour tension of HquicJ 

 ammonia at atmospheric temperature being from 7 

 to 8 atm., it will be seen th<at this is neg^ligible in 

 the gas obtained by the Claude process, but most 

 appreciable with the gas obtained by the Badische 

 process. It is sufficient, in Claude's apparatus, to 

 pass the gas throuj^^h coils immersed in cooling water 

 in order to separate practicallv all the ammonia, and 

 the residual gas, after separation of liquefied ammonia, 

 is sent directly, without further compression, to a 

 second catalyst chamber. Three or four catalyst 

 chambers suffice to convert the gas into ammonia. 

 In the Badische process, on the contrarv, it is neces- 

 sary to wash out the ammonia with water under pres- 

 sure, requiring a complicated anoaratus and expendi- 

 ture of work to bring the gas again to 200 atm. after 

 mixinjT;- with fresh gas, and 15 catalyst chambers are 

 required. It is also necessary to use heat to separate 

 the ammonia gas from the solution so obtained, 

 whereas in Claude's process the liquefied ammonia is 

 merely allowed to evaporate, producing cold which 

 can be utilised. 



The Claude process, which offers great possibilities 

 in the synthesis of ammonia and in the utilisation of 

 atmospheric nitrogen, is to be installed in England. 

 The patent rijrhts have been acquired by the Cumber- 

 land Coal and Chemicals Co., who are to erect a works 

 in the centre of the coke-oven district in Cumberland. 



Field-work of the Smithsonian Institution. 



T^HE Smithsonian Institution has just issued its 

 -■• annual Exploration Pamphlet, describing and 

 illustrating its scientific field-work throughout the world 

 during 1920. Twenty-three separate expeditions were 

 in the field carrying on researches in geology, palae- 

 ontology, zoology, botany, astrophysics, anthropology, 

 archaeology, and ethnology, and the regions visited 

 included the Canadian Rockies, fourteen States of the 

 United States, Haiti, Jamaica, four countries of South 

 America, Africa from the Cape to Cairo, China, 

 Japan, Korea, Manchuria, Mongo'ia, Australia, and 

 the Hawaian Islands. The pamphlet serves as a pre- 

 NO. 2702, VOL. 107] 



liminary announcement of the results obtained, though 

 many of the expeditions will be more fully described 

 later in the various series of publications under the 

 direction of the Smithsonian Institution. 



Dr. C. D. Walcott, secretary of the Smithsonian 

 Institution, continued his geological work in the Cam- 

 brian rocks of the Canadian Rocky Mountains in the 

 region north-east of Banff, Alberta. The work was 

 hindered considerably during July and .August by 

 forest fires and by continuous stormy weather in Sep- 

 tember, but the particular questions involved in the 

 season's research were settled satisf actor ilv, and some 



