of the Fishery Board for Scotland S 86 



APPENDIX F.— No. XII. , 



REPORT on tlie PHYSICAL OBSERVATIONS made for the 

 FISHERY BOARD for SCOTLAND during the Antumn of 1883 

 in the Moray Firth. By John Gibson, Ph.D., Senior Demonstrator ; 

 of Chemistry, University of Edinburghu With Plates VI. and VII. • 



Eaely in August 1883 I was mvited by Professor Cossar Ewart to join 

 a scientific expedition to the Moray Firth, and to carry out physical and 

 chemical work in connection therewith. As only a very few days were at 

 my disposal it was not possible to make preparations for any very extended 

 or systematic series of observations. The expedition was in fact of a 

 tentative nature, and I therefore devoted myself chiefly to laying down j 

 lines for that future work for which it was then hoped the indispensable I, 

 facilities would be granted by Government in the year following. 



The delay in drawing up this report has been in part caused by cir- 

 cumstances beyond my control, but has mainly arisen from my having 

 been led into a somewhat extended research, in order to ascertain the 

 degree of accuracy of the elegant method for the determination of specific i 

 gravities of liquids originally due to Sprengel. (Chem. Soc. Jour. [2], xi. \ 

 577). The greater portion of this report consists of a description of a j: 

 special adaptation of this method to hydrographic work, and of a dis- j 

 cussion of the results which I have obtained by it. j! 



The most of the work accomplished by me during the expedition was il 

 carried out on board H.M.S. 'Jackal,' and consisted chiefly of tempera- j 

 tare observations and in the collection of samples of water at different I 

 points or stations, as opportunity presented itself, between the intervals of ■ 

 the dredging, which occupied the greater part of each day, while the ; 

 expedition lasted. | 



Column three of Table I. gives the number of the station as marked upon ; 

 the Admiralty Chart used during the Expedition. i; 



Station means simply place at which a halt was made in order to let | 

 down the dredge or trawl, to take temperatures, or to collect samples. The I 

 ]iosition of each station was determined as closely as possible by cross i; 

 bearings. The principal stations are indicated in the chart (Plate VII.). I 



For these I am indebted chiefly to the kind courtesy of Lieutenant 

 Steele of H.M.S. 'Jackal.' During the latter part of the Expedition they ; 

 were determined by Mr J. A. Macdonald, in command of the Fishery 

 Board cruiser ' Vigilant,' on board of which vessel the latter part of the 

 observations, viz., those taken from September the 11th to September 

 21st inclusive, were made. To him also I am much indebted for the 

 assistance which he at all times so readily gave, and for the interest which 

 he took in the work. 



The temperatures were taken partly with ordinary maximum and 

 minimum thermometers (17, 18, and 19 in Table T.) by Cassella, and 

 belonging to the Admiralty. By September 5th I was able to use one 

 of Negretti and Zambra's reversing thermometers (R, in Table I.), fitted 

 in iCommander Magnaghi's frame. All the thermometers used were care- 

 fully compared with a Kew standard, but within the range of temperature 

 I niet with, no errors were detected sufficient to justify the application of 

 any correction. The temperatures given in Table T. are therefore those 

 actually observed and noted down at the time. 



The depths given in column four were obtained by the sounding line, 

 and Mo not pretend to any great accuracy. 



This table requires no farther explanation. 



