April 21, 1892] 



NA TURE 



589 



Baker; and "Notes on Mexican Archaeology," by F. W. 

 Warner. 



Messrs. Wm. Blackwood and Sons will publish, in the 

 course of a few days, a short treatise on " Farmyard Manure,'' 

 by Mr. C. M. Aikman, Lecturer on Agricultural Chemistry, 

 West of Scotland Technical College. 



Messrs. Smith, Elder, and Co. have issued a third edition 

 of the "Junior Course of Practical Zoology," by Prof. A. 

 Milnes Marshall, assisted by Dr. C. Herbert Hurst. Advantage 

 has been freely taken of corrections and suggestions received 

 from many sources. The whole book has been carefully revised, 

 and some new figures have been added. 



The Royal University of Ireland has issued a supplement to 

 its Calendar for the year 1892. It includes the examination 

 papers used in 1891. 



A NEW series of compounds, in which the'hydroxylic hydrogen 

 of phenols is replaced by the element titanium, are described by 

 M. Levy in the April number of the Annales de Chimie et de 

 Physique. The first member of the series, that derived from the 

 simplest phenol, carbolic acid, CgHjOH, possesses the composi- 

 tion Ti04(C6H3)4 or TilCgHjOi- The discovery of these somewhat 

 remarkable compounds was the result of an inves ligation con- 

 cerning a colour reaction of titanic acid. M. Levy had observed 

 that when a small quantity of titanic acid was brought into 

 contact with sulphuric acid containing a little phenol, a deep 

 red coloration was produced. The red colouring matter was 

 soluble in the oil of vitriol, but was decomposed when the 

 solution was diluted with water or neutralized by alkalies. The 

 red substance has, however, been isolated by employing another 

 mode of preparation, and proves to be the titanium phenylate, 

 Ti(C6H50)4, above mentioned. It may readily be prepared by 

 the action of titanium tetrachloride, TiClj, upon a solution of 

 phenol in benzene. The titanium tetrachloride, in quantity one 

 molecular equivalent, is poured directly into the solution of four 

 molecular equivalents of phenol, when a very energetic action 

 occurs with liberation of a large quantity of hydrochloric acid 

 gas. The last traces of hydrochloric acid are removed by means 

 of a current of hydrogen, the reaction flask being warmed to 

 about 70° by means of a water-bath and fitted with a reflux 

 condenser. Upon the completion of the reaction the benzene is 

 evaporated off, when the new compound is left behind in the 

 form of large crystals. The crude substance thus prepared is 

 then recrystallized from a mixture of benzene and petroleum, 

 when it is obtained in the form of rhombohedral crystals of the 

 colour of bichromate of potash, and which, like the latter 

 compound, yield a powder much yellower in colour upon 

 pulverization. The crystals are readily soluble in benzene^ 

 toluene, alcohol, or ether. They also dissolve in concentrated 

 sulphuric acid, producing the same red oil which is formed in 

 the colour reaction above described. The action of water upon 

 the crystals of titanium phenylate appears to be of the nature of 

 saponification. It occurs in at least two stages, a compound 

 Ti04H2(C6Hg)2 being first produced ; this intermediate com- 

 pound passes eventually into titanic acid, carbolic acid being at 

 the same time formed in the solution. Fuming nitric acid, when 

 in large excess, converts titanium phenylate into titanic and 

 picric acids ; but if only a small quantity of nitric acid is employed, 

 titanium picrate is precipitated in the form of a black insoluble 

 substance. Nascent hydrogen, liberated by means of dilute 

 hydrochloric acid and zinc or tin, reduces the titanium in titanium 

 phenylate to titanium trichloride, with production of the usual 

 violet coloration due to that compound. Gaseous chlorine 

 rapidly converts the crystals of titanium phenylate into titanium 

 tetrachloride and the di-chiorine derivative of phenol. In 

 addition to titanium phenylate, the analogous compounds with 

 the cresol phenols, thymol, naphthol, resorcinol, and salicylic 

 NO. TI73. VOL. 45] 



acid have been prepared. They are all red or brownish-red 

 solid substances possessing properties similar to those of titanium 

 phenylate. 



The additions to the Zoological Society's Gardens during the 

 past week include a Grivet Monkey {Cercopithecus griseo- 

 viridis i ) from North-east Africa, presented by Miss G. A. 

 Vicars ; a Leopard (Felis pardtts <J) from Ceylon, presented by 

 Mr. Marcus W. Miliett ; a Lesser Sulphur-crested Cockatoo 

 (Cacatua sulphured) from Moluccas, presented by Mrs. Kate 

 Taylor ; a Greater Sulphur-crested Cockatoo (Cacatua galerita) 

 from Australia, presented by Mr. Earle Whitcombe ; a Common 

 Zebra [Eqmcs zebra ? ) from South Africa, a Wonga-wonga 

 Pigeon {Leucosarcia picata ? ) from New South Wales, a 

 Cereopsis Goose {Cereopsis nov(Z-hollandice) from Australia, 

 deposited; a Yak {Poephagus grunniens <J ), born in the 

 Gardens. 



OUR ASTRONOMICAL. COLUMN. 



Astronomy at the Paris Academy, April ii. — MM. 

 Perigaud and Boquet have independently made some observa- 

 tions of the latitude of Paris Observatory, one of the objects of 

 the investigation being to determine whether the value under- 

 went a periodic variation. The two series of observations only 

 differ from one another by about one-hundredth of a second of 

 arc; the value derived from them is 48° 50' n"oi. No 

 definite evidence of variability was obtained. Admiral Mou- 

 chez, in commenting upon these observations and a dis- 

 cussion of the latitude of the Observatory, made by M. 

 Guillot in 1879, said that doubtless the variation found at other 

 Observatories was wholly or in large part due to the influence of 

 temperature on astronomical refraction. A photograph taken 

 by Dr. Gill was presented by Admiral Mouchez to the 

 Academy. It embraced an area of 2° x 2°, and on this sky- 

 space from 30,000 to 40,000 stars had left their impressions, 

 besides two nebulae. The exposure given was 3h. 12m. instead 

 of the ih. which is given to plates for the "Carte du Ciel." If 

 this exposure were possible for the whole photographic map of 

 the heavens, about 300,000,000 stars would record their exist- 

 ence instead of 30,000,000. 



Swift's and Denning's comets have been observed at Bordeaux 

 on several occasions. The former is described as very brilliant, 

 with a nucleus of about the seventh or eighth magnitude, a head 

 about 8' in diameter, and the trace of a tail. M. Landerer has 

 compared the calculated time of eclipses of Jupiter's satellites 

 given in the Connaissance des Temps with the actual times 

 observed. The agreement between the two is very remarkable. 



Solar Heat. — Volume ii. of the Transactions of the Astro- 

 nomical and Physical Society of Toronto (1891) has recently 

 been issued. It contains several interesting papers, one of 

 which, by Dr. Joseph Morrison, deals with solar heat. Two 

 theories have been advanced to account for the source and 

 maintenance of the heat of the sun. One ascribes the heat to 

 the energy of meteoritic matter falling on the sun, the other 

 asserts that the supply of heat is kept up by the slow contraction 

 of the sun's bulk. Taking the "solar constant " as twenty-five 

 calories per square metre per minute. Dr. Morrison calculates 

 that the linear contraction of the radius of the sun which is 

 requisite to keep up the present rate of radiation, is 0*000004972 

 feet in i second, or 156 9 feet in a year, or 29716 miles in 

 a thousand years. "Now 450 miles of the sun's diameter 

 subtends at the earth an angle of i", and therefore it would 

 require 7575 years for the sun's angular diameter to be reduced 

 by i" of arc, which is the smallest angle that can be accurately 

 measured on the solar disk." With regard to the meteoritic 

 theory of solar energy, a calculation shows that a quantity of 

 matter which weighs one pound falling freely from infinity to 

 the sun would develop by its kinetic energy 82,340,000 units of 

 heat. From this it can be found that the heat radiated could 

 be developed by the annual impact on the sun of a quantity of 

 meteoritic matter a trifle greater than i/iooth of the earth's 

 mass, and having a velocity of 382 6 miles per second. 



Periodic Variations in Latitude.— Mr. Chandler, in 

 some recent numbers (248 and 249) of the Astronomical /ournal, 

 announced the discovery that the earth's axis of rotation revolves 

 round her axis of maximum moment of inertia in a period of 



