April i8, 1895] 



NA TURE 



593 



tween phosphorus penlachloride and ammonium chloride ; it 

 is a substance almost as stable a^ the triple compound, and 

 yields on saponification the acid (PNO.jHolj, which is likewise 

 a stable body. Moreover, the acid corresponding to the triple 

 compound has been isolated, and also a higher chloride 

 (PNCl2)x of an oily character, and whose molecular weight has 

 not yet been ascertained. In describing his repetition of Dr. 

 Gladstone's work, Mr. Stokes incidentally mentions the in- 

 teresting circumstance that the triple compound readily forms 

 enormous crystals, well-developed prisms several inches long 

 and of considerable thickness being frequently deposited from 

 benzene, and indeed their size appears only to be limited by 

 that of the containing vessel and the bulk of solution. These 

 crystals melt at H4°. The quadruple compound melts at I23°"5, 

 and boils at the normal pressure at 256' '5. It crystallises well 

 in colourless prisms, which are usually much smaller than those 

 of the triple compound, and exhibit great tendency to develop 

 anacicular character. It is less soluble in alcohol and benzene than 

 the latter compound ; it may berecrystallised from glacial acetic 

 acid, but it exhibits a great aversion for water, not being wet by 

 it, and consequently the crystals float on water. It dissolves 

 in hot ccncentrated oil of vitriol, but upon boiling most of it 

 sublimes unchanged, an evidence of its great stability. Its 

 vapour is endowed with a pleasant aromatic odour, but inhala- 

 tion of more than traces is followed in two or three hours by 

 alarming difficulty in breathing and persistent irritation of the 

 air passages. Its vapour density was determined in an atmo- 

 sphere of hydrogen, and indicated the quadruple formul.- , Even 

 boiling water exerts only a very slight action upon it ; but a 

 smooth decompo.sition is effected by dissolving in ether, and 

 repeatedly agitating with water. The acid produced is 

 deposited from the water in crystals having the composition 

 (PN05Ho)4-)-2H30. This interesting acid readily decomposes 

 soluble chlorides, nitrates, and sulphates, forming three series 

 of salts, in which respectively one-fourth, one-hall, and all the 

 hydrogen is replaced by the metal. The free acid is so highly 

 stable that it may be boiled for hours with nitric acid or aqua 

 regia without decomposition. Further details concerning it, 

 and the other compounds isolated, will shortly be published. 



BIOLOGICAL 



WORK ON THE ILLINOIS 

 RIVER. 



T LLINOIS possesses a good Laboratory of Natural History, 

 in which Prof. S. A. Forbes, with a number of assistant 

 entomologists and zoologists, carry on investigations of value 

 to science and the State. A report on the work of the Labora- 

 tory during the past two years has recently been issue d. To us 

 the points of special interest with which it deals are (i) the 

 establishment, in 1894, of a biological station for the con- 

 tinuous investigation of the aquatic life of the Illinois River, 

 and ils dependent waters, near Havana; and (2) an elaborate 

 expeiimental research carried on during the past year to deter- 

 mine means for the destruction of the chinch bug, and especially 

 for the dissemination of the contagious diseases of that insect. 

 This investigation was undertaken by the Laboratory staff, 

 with the co-operalion of the State Agricultural Experiment 

 Station. 



We have already noted the establishment of the biological 

 station (Nature, vol. 1. p. 275, 1894), but as it is the first 

 inland aquatic biological station in America, manned and 

 equipped for continuous investigation, the following further 

 details ate interesting. By the kindness of Prof. Forbes, we 

 are able to illustrate the description with two of the fifteen fine 

 process plates contained in his report. 



The Station was opened just a year ago. Its general objects 

 are to provide additional facilities and resources for the 

 study of the natural history survey of the State, now being 

 carried on by the State Laboratory of Natural History ; to 

 contribute to a thorough scientific knowledge of the whole 

 system of life existing in the waters of this State, with a 

 view to economic as well as educational applications, and 

 especially with reference to the improvement of fish culture 

 and to the prevention of a progressive pollution of Illinois 

 streams and lakes ; to occupy a rich and promising field of 

 original biological investigation hitherto largely overlooked or 

 neglected, not only in .\merica but throughout the world ; and 

 to increase the resources of the zoological and botanical depart- 



NO. 1329, VOL. 51] 



mcnts of the University of Illinois, by providing means and 

 facilities for special lines of both graduate and undergraduate 

 work and study, for those taking major courses in these depart- 

 ments. 



The Station differs from most of the small number of similar 

 stations^thus far established in the United Stales, in the fact that 

 its main object is investigation instead of instruction, the latter 

 being a secondary, and at present an incidental, object only. 

 It has for its field the entire system of life in the Illinois River 

 and connected lakes and other adjacent waters, and it is Prof. 

 Forbes' intention to extend the work as rapidly as possible to 

 the Mississippi River system, thus making a beginning on a 

 comprehensive work in the general field of the aquatic life of the 

 Mississippi Valley, in all its relations, scientific and economic. 



The special subject which Prof. Forbes fixed upon as the 

 point of direction towards which all the studies shall tend, is 

 the effect, on the aquatic plant and animal life of a region, pro- 

 duced by the periodical overflow and gradual recession of the 

 waters of great rivers, phenomena of which the Illinois and 

 Mississippi rivers afford excellent and strongly marked examples. 

 This field of research is entirely fresh, and at the same time is 

 highly interesting and important. 



As an incidental, but by no means unimportant, result of the 

 work, material will be accumulated for a comparison of the 

 chemical and biological conditions of the waters of the Illinois 

 River, at the present time, and after the opening of ihe Chicago 

 drainage canal. 



The practical importance of the undertaking, as affording the 

 only sound basis for a scientific fish culture, will be fully re- 

 cognised by all who are seeking to apply scientific methods of 

 investigation to economic problems. 



It is pointed out that the Station will also serve as a 

 centre of interest and activity for University students engaged 

 on zoological and botanical subjects. Not many years ago 

 biological instruction in American colleges was mostly derived 

 from books ; of late it has been largely obtained in laboratories 

 instead ; but Prof. Forbes believes that the mere book-worm is 

 hardly narrower and more mechanical than the mere laboratory 

 grub. Both have sr.ffered, and almost equally, from a lack of 

 opportunity to study nature alive. One knows about as much 

 as the other of the real aspect of living nature, and of the ways 

 in which living things limit and determine each others' activities 

 and characters, or in which all are determined by the inorganic 

 environment. 



Means are provided by which students, and intending teachers 

 of biology, may be given a wider knowledge of their subject, 

 and where they may investigate experimentally the prob- 

 lems of mutual influences and relationship in the living 

 world. 



Possibly still more important is the opportunity which the 

 Station will offer, when permanently established and fairly well 

 developed, to the independent student and investigator, 

 zoological or botanical, who may desire to pursue his studies in 

 the field covered by the operations. It is a part of the plan of 

 organisation and equipment to receive and assist in every 

 practicable way advanced students and investigators of this 

 description, from whatever place they may come. 



Havana was selected as the site of the Station because of 

 several unique advantages offered by that locality. Streams 

 and lakes illustrating practically all the typical Illinois River 

 situations are to be found there, convenient of access from a 

 central point, and from each other. An extensive sandy bluff, 

 commonly well shaded and oozing spring w.ater at ils foot, 

 borders the river bottom on the east, and introduces several un- 

 usual features ol interest to the oecologist, besides affording a 

 clean and hard shore to work from, dry, shady, and well-drained 

 camping ground, and an abundance of very pure cold water at 

 all times of the year. 



A " cabin boat " was used as a field headquarters, and 

 stationed on Quiver Lake, two and a half miles above Havana. 

 It carried the seines, sounding lines, atrial and aquatic ther- 

 mometers, dredges, surface nets, Birge nets, insect nets, 

 plankton apparatus, and other collecting equipment, together 

 with microscopes, reagents, a small working library, a large 

 number of special breeding cages for rearing aquatic insects, 

 and a few small aquaria. This boat was provided with sleeping 

 accommodation for four men, and with a well-furnished 

 kitchen. 



The greater part of the field work was done on seven regular 

 stations, visited periodically throughout the year ; two on the 



