110 Observations on the Temperature of the 



Clydesdale on the afternoon of the 5th, and morning of the 

 6th ; during the short space of fifteen hours, rain was depo- 

 sited on the soil to a depth of 2 inches ; in consequence of 

 which, every stream and rivulet was swollen to the fullest 

 extent. These speedily changed the estuary water from its 

 usual transparent appearance, into an opaque, dull-red, 

 muddy hue, and produced the increase of temperature over a 

 large surface, — ^a result, arising from a storm, which it is 

 probable that a week or a fortnight of the most brilliant 

 summer sun could not have effected ; for the observation on 

 30th June only exceeded by half a degree that of the pre- 

 vious summer, while the Mersey water was considerably 

 warmer than the hottest period of 1845. 



On comparing the greatest temperatures of the two last 

 summers it will be seen, that this year, although the rates 

 range higher from June to September, by the end of October 

 the influence of the warmer season had lost its effect on the 

 temperature of the Mersey water, which was then down to a 

 point a little below the coldest of October 1845. 



In my former communication I alluded to the appearance 

 of luminous crested waves being connected with the chemi- 

 cal action of the water absorbing oxygen at the moment of 

 breaking. In Brodick Bay, in Arran, during the calm, hazy 

 weather of the third week of September, I noticed an appear- 

 ance on the surface of the water which tends to strengthen 

 this view, although I would by no means wish to state it as 

 the sole source of luminous waves, when it is so well ascer- 

 tained that many of the marine animalculse can emit phos- 

 phorescent light. 



In Brodick, the weather had been very calm for some days, 

 the temperature of the water on the 15th, 16th, and 17th, was 

 61°. During the 16th, the sea had a glassy surface, and so 

 transparent, that objects at the depth of 10 or 12 feet were 

 seen distinctly. In the morning and evening, I observed on 

 the shore, at two places above a mile apart, that where any 

 object broke the smooth surface of the sea, there appeared 

 to be a mixing together of two transparent media of different 

 densities ; where a projecting piece of rock, by the tidal cur- 



