126 



NA TURE 



[August 2, 1894 



bridgeshire, under the Parish Coancils Act. A resolution pro- 

 te<ling against this cession was unanimously passed, and a copy 

 ordered to be sent to the Essex County Council and to the Essex 

 Members of Parliament. The members next proceeded to 

 inspect an ancient earthwork in a wood near the park, which 

 earthwork is entered as a camp in the ordnance map. It con- 

 sists of a well-defined rampart and ditch, and is of an oblong 

 form, with a spur at one angle. The site is now known as 

 "Fortification Wood," but was formerly known as the " Defence 

 of Navestock." The party next proceeded towards the Roding 

 Valley, and were conveyed to Curtismill Green, an outlying 

 fragment of old Hainhault Forest, which, with Epping Forest, 

 formerly constituted the Foiest of Waltham. Here they were 

 shown an upright stone, which the conductors had identified as 

 " Richard's Stone," one of the boundary stones set up at the 

 time of the perambulation of the Essex Forest in 1641-1642. 

 Standing by this stone, marking the extreme north-eastern 

 extension of the old forest. Prof. Meldola gave a short account 

 of the history of the perambulation, and stated that with his 

 colleague, Mr. Coode Hore, and Mr. William Cole, the hon. 

 secretary, and his brothers, they had now found five out of the 

 seven boundary stones referred to in the perambulation. The 

 fragment of primitive forest between " Richard's Stone " and 

 the "Navestock Stone" was much admired, as far as time 

 permitted an inspection, and a desire was expressed that steps 

 should be taken for securing the permanent preservation of all 

 these interesting boundary marks, the more especially as the 

 forest of Hainhault has, with the exception of a few isolated 

 patches, been entirely cultivated out of existence. From 

 " Richard's Stone" the party drove through some of the most 

 picturesque parts of the county to SDuth Weald, where, at the 

 "Tower Arms," tea was awaiting them. After tea another meet- 

 ing was convened for the purpose of hearing a most interesting 

 paper by Mr. Coode Hore, in which he gave a series of notes 

 on the history of Navestock in Saxon and Norman times, and 

 made reference to the prehistoric remains visited in the course 

 of the day. 



The annual report of the Director of the Royal Botanic 

 Garden, Calcutta, for the year 1S93-94, has just reached us. 

 During the year the Herbarium was enriched by more than 

 16,000 specimens, and the Garden in return sent out numerous 

 specimens to various botanical institutions in ditTcrent parts of 

 the world. Reference is made to a great storm which raged for 

 nearly the whole of three days in the month of May, and 

 the damage done was so great that for about six weeks 

 after its occurrence the whole of the out-door labour staff was 

 engaged in making repairs. A more suitable platform for 

 Colonel Kyd's monument was erected, the roads in the grounds 

 were generally improved, and the gardens are reported to have 

 been maintained in a high state of efficiency. 



M. L. Cayeox (Bull. Soc. Geol. France) describes radio- 

 iarians from rocks in lirittany which are generally admitted to 

 be pre-Cambrian. They occur in siliceous bands in the " Phyl- 

 Udei de Saint- L'l." The evidence for the pre-Cambrian age 

 of these beds is stated by Dr. liirrois. Minyof the radio- 

 larians described belong to the genera still existing. 



A PAPER on the " Shanta-Chico Series," of N. California 

 and Oregon (Bull. Geol. Sic. Aner.), by Messrs. J. S. Diller 

 and T. W. Stanton, is interesting as discussing the limits of 

 the Cretaceous and Jurassic formations on the Pacific Coast. 

 The series has a maximum thickness, on Elder Creek, Tehama 

 Co., California, of 30,000 feet ; the whole set of beds graduat- 

 ing into one another a< one continuous series. It was formerly 

 supposed that the lower (Knoxville) bedi graJuate into the 

 Mariposa l>cds— the highes: Jurassic ; the authors contend that 

 there it both a physical and palxontolo^ical break between 



NO. 1292, VOL. 50] 



them. The highest Cretaceous rocks are not here represented, 

 and the Ttjon beds, which probably are not the oldest Eocene, 

 rest unconformably upon the Chico series. In Middle and 

 Southern California the Tejon beds are believed to be con- 

 formable to the Chico beds. 



Prok. H. F. Osborn discusses the characters and faunal 

 relations of the Laramie Mammals {Bull. .Amer. Mus. Nat. 

 Hist. vol. v., p. 311), and shows that they are more nearly 

 related to the Puerco (Eocene) mammals than they are to those 

 of the Jurassic series. This is specially illustr.ated by the 

 evolution of the teeth. In the same volume, there are papers 

 by Prof. Osborn, Dr. J. L. Wortman, and Ch. Earle, on the 

 Lower Miocene mammalia of North .\merica. The White 

 River deposits have a maximum thickness of about Soo feet, and 

 they represent a great period of time, during which the Titan- 

 otheriida;, Rhinocerotidas, Equida;, and Oreodontid;v underwent 

 considerable modification, amounting in some cases to changes 

 of true generic significance. 



A NEW design for large spectroscopic slits is described by 

 Mr. Wadsworth in the current number of the American 

 fouriial of Science. Of the various forms of double motion 

 spectroscope slits which have been designed, the two forms in 

 most common use are the parallel ruler form, as fitted to most 

 German instruments, and that form in which the jaws slide in 

 guides, and are moved simultaneously in opposite directions by 

 a right and left hand screw. The first form is convenient but 

 somewhat bulky, and makes it difficult to determine the exact 

 width of the slit. The second form, in which the screw is 

 necessarily at one side of the jaw, gives rise to a twisting strain 

 tending to make the slit wider at one end than at the other, aik 

 objection which becomes very serious in slits above 5 cm. in 

 length. The author's new form, designed for Prof. Langley, 

 has the advantage of giving a central thrust on both jaws while 

 keeping the slit accur.ately centred. This is accomplished by 

 making the milled head move the whole jaw system along the 

 slit plate by means of a nut screwed to the latter, while another 

 screw on the same shaft, but of double the pitch, moves the 

 nearer jaw independently in the opposite direction. Thus the 

 centre of the slit remains fixed, the jaws opening out from it. A 

 spring provides for the return motion, and takes up all back 

 lash in the screw. The graduated head gives by its motion over 

 a graduated drum the whole number of turns and fractions of a 

 turn, enabling the width of the slit to be determined at a glance. 

 The thrust being central, there is no tendency to twist the jaws 

 in their guides'. The slit has a clear opening of 10 cm. 



It appears that the public in Brooklyn, U.S.A., are making 

 use of the stray current from the electrical tramways, 

 driving motors and lighting lamps, by connecting the terminals 

 to the metallic framework of the overhead railways and to the 

 water-pipes ; while it is proposed in one of the suburban tele- 

 phone exchanges to utilise the above current, and do away with 

 the batteries. The loss of energy on the .\merican lines where 

 the current is supplied by a trolley wire, and the return takes place 

 by the rail, is very considerable, and the above use of the stray 

 current is much more likely to draw the attention of the tram- 

 way companies to these losses than the corrosion of the water- 

 and gas-pipes, the damage to which we have on previous 

 occasions referred. 



AccoRUINf. to the Pioneer Mail, Allahabad, the anlhro- 

 pometrical system of identification has already proved of 

 practical use in liengal. Previous convictions against six men, 

 who had been sentenced in districts beyond Calcutta, were 

 traced by its means. 



£ngi»eering (or ]u]y 27 is a special numljcr, and is, for the 

 most part, taken up with a description (with illustrations) of 

 the various mills and appliances used in the manufacture oi 



