February 8, 1894J 



NATURE 



347 



of oil is said to have taken place in July, 1892, when the water- 

 level was low, and this has continued at intervals, but in smaller 

 quantities, since that date. Ashwick is shown on the Geological 

 Survey map to stand at the northern edge of the carboniferous 

 limestone : the beds have a high dip to the north, passing under 



the millstone grit and the coal-measures of the Radstock area. 

 Indications of petroleum are also known in other wells and 

 springs in the neighbourhood. The matter is now being inves- 

 tigt.ted by Mr. Boverton Redwood and Mr. W. Topley, under 



whose directions further explorations will be made. 



The phosphatic marls of New Jersey have long been known ; 

 they have been worked for fertilisers since 1768. Mr. W. 

 Bullock Clark has published a paper •' On the Cretaceous and 

 Tertiary Formations of New Jersey." (Ann. Rep. of the State 

 Geologist, 1892.) The origin of a glauconitic greensand is fully 

 discussed, and reference made to recent deep-sea research. 

 Coloured reproductions are given of Murray and Renard's plates 

 in the Chalkuger Expedition Report, exhibiting phases in the 

 formation of glauconite. The greensands occur most commonly 

 near the boundary lines between the shallow and deep-water 

 zones, but not opposite the mouths of large rivers, nor where 

 strong currents prevail. In making the detailed survey in New 

 Jersey, a small boring apparatus has been used, which seems, 

 from the description given, to be simpler and more portable 

 than that employed on the Belgian and English surveys. It is 

 made of half-inch gas-piping, in lengths of 10 feet. This giyes 

 good results to a depth of 30 feet. 



Mr. Clark's paper is further illustrated by prints from 

 photographs. Some of those, e.g. " View among the Navesink 

 Highlands,"' suggest nothing so much as an ultra-" impres- 

 sionist " daub, all blur and no colour I The professional photo- 

 grapher complains of the hypercritical eye of his fair sex con- 

 stituency ; one could wish that nature had a word to say for 

 herself. The photographic camera is fast coming to be con- 

 sidered part of the equipment of the geologist. If men, whose 

 movements in the field are already well burdened by hammer, 

 compass, knapsack, and specimens, are willing to add to those 

 the inconvenience of a camera, there must be great advantage to 

 be got from photography. But what advantage will be derived 

 from an occasional lucky hit ? It would be difficult to name 

 the science now that does not utilise photography. Clearly the 

 time has come when another "optional" may be added to the 

 subjects of the complete curriculum. At any rate, science must 

 recognise photography at its professional value, and must refuse 

 bad photographs and worse prints. 



For some time past the United States Hydrographic Office 

 has been collecting information about jthe meteorology of the 

 North Pacific Ocean, with the intention of utilising it for the 

 benefit of seamen, and it has recently issued an advance Pilot 

 Chart of that ocean for the month of January, 1894, on the same 

 principle as the Pilot Chart for the North Atlantic Ocean, which 

 has often been referred to in our columns. The hydrographer 

 states that, if Congress grants the necessary funds, it is proposed 

 to issue on the first day of each month a chart showing for the 

 Succeeding month, by deduction from accumulated observations, 

 the winds and currents to be expected, the regions of prevailing 

 fog and rain, the most advantageous' routes to be followed by sail 

 and by steam, &c. The amount of information available for the 

 Pacific is greatly inferior to that for the Atlantic, but if the 

 support and cooperation sought for are freely given by those in- 

 terested in enhancing the safety of navigation, the undertaking 

 will undoubtedly become a very valuable contribution to mari- 

 time meteorology. 



M. H. Parentv has been investigating the forms of steam 

 ijels from various orifices, and has published his results in the 



NO. 126;, VOL. 49] 



last number of the Cotnptes Rendus. The diagrams accom- 

 panying the paper, in which regions of different pressures are 

 shaded differently, exhibit some curious fluctuations, which may 

 be described as a series of nodes and ventral segments proceed- 

 ing outwards from the orifice. These fluctuations are due to 

 the interference between the outgoing waves of steam pressure 

 and those reflected back by the air. In the case of a con- 

 vergent elliptical orifice of 13', three nodes were found with 

 pressures of 1 15, 165 and 138 cm. respectively, that at the orifice 

 being 285 cm. or 375 atmospheres. All the nodes occurred 

 within 2 cm. of the orifice. They were found by means of an 

 air-manometer provided with very finely-drawn glass tubes. 

 It appears that the position and value of the nodes or condensa- 

 tions depend upon the difference of pressure between the boiler 

 and the atmosphere, and the form of the orifice. At very high 

 pressures the jet assumes an approximately paraboloidal shape, 

 such as would be assumed by a liquid jet falling upon a disc of 

 the size of the orifice. A further conclusion reached by M. 

 Parenty is that the highest attainable velocity of etillux is 

 the limiting velocity of sound in the medium concerned. 



The curious polarisation phenomena obtained with very small 

 electrodes in a sulphuric acid voltameter through which a strong 

 current passes, accounts of which have appeared in Wiedernann s 

 Annalen for the winter of 1892, suggested to Dr. L. Arons the 

 question as to what would take place at a very thin and small 

 metallic partition in a voltameter. Some preliminary observa- 

 tions made by Dr. Arons showed that when a piece of gold-leaf 

 was pasted over a hole 15 mm. in diameter bored through a 

 glass partition in a voltameter, there was no visible development 

 of gas at the partition ; while with platinum foil '02 mm. thick 

 there was a profuse development of gas with the same current 

 strength. A very thorough investigation of the polarisation 

 phenomena upon thin metal partitions has been carried out by 

 Mr. John Daniel, an account of which is published in the 

 Philosophical Magazine for February. The author has examined 

 partitions made of gold, platinum, silver, and aluminium, and 

 finds that, in good conducting solutions of sulphuric acid, 

 copper sulphate, and common salt, the critical thickness, below 

 which there is no polarisation, is for gold between "00009 mm. 

 and "0004 mm., while for plates more than '004 mm. thick 

 the polarisation is as great as for very thick plates. The author 

 finds that the polarisation of " thick ' plates is about the same 

 for all currents between o"2 ampere and 0"0i ampere, provided 

 time be allowed in each case for the current to become constant. 

 With " thin " plates, however, the polarisation depends upon 

 the current. By thick plates we mean those with a thickness 

 greater than 0*004 mm., and by thin plates those having a 

 thickness less than this quantity. 



The same number of the Philosophical Magazine contains a 

 paper by Mr. W. H. Steele, on the thermoelectric diagram for 

 some pure metals. From some thermoelectric observations he 

 had made, the author was led to suspect that the lines given by 

 Prof. Tait in his thermoelectric diagram were not quite accurate, 

 and he has therefore undertaken the measurements necessary to 

 construct a diagram, using metals in as great a state of purity 

 as possible. The metals used are aluminium, tin, lead, zinc, 

 thallium, silver, gold, copper, cadmium, and antimony. The 

 electromotive force for a temperature difference of about 100' C. 

 was in each case compared with that of a standard Clark cell 

 made according to Lord Rayleigh's instructions. 



The distribution of zymotic disease by sewer air is a question 

 still sub jndice, and in order to throw, if possible, some 

 additional light on the subject the London County Council asked 

 Mr. Laws to make some investigations on the air in some of the 

 London sewers. The report has recently been presented and 

 published. The principal experiments were made^in a sewer run- 



