1829.] Scientific Intelligence. 71 



barometrical observation, maybe considered very small. For- 

 merly the heiglit was reckoned only 5926 French feet. This is 

 the height given in the Almanack of Gotlia. — (Ibid. p. 197.) 



XI. Further Observations on the Double Rainboio seen at Paislei/. 



By Mr. Macome. 



(To Dr. Thomson.) 

 DEAR SIR, Paishy, Nov. \6, 1819. 



The kindness with which you gratified me with a solution of 

 such difficulties in chemistry as opposed my attempts to acquire 

 some knowledge of that fascinating science, induced me to 

 trouble you with a notice of a singular rainbow 1 had lately 

 witnessed, and in v.hich the more refrangible colouring rays 

 were distinctly repeated — an appearance which I could not 

 account for. As the statement, however, was drawn up uithout 

 the most distant view towards pubhcation, 1 perceive it is not 

 sufficiently explicit in detailing the principal attendant circum- 

 stance — a knowledge of which may probably lead to an explana- 

 tion of the phenomenon. While viewing a rainbow of the usual 

 appearance, a driving shower from the south-west was moving 

 in a direction which would cross obliquely a line uniting me with 

 the southern limb of the arch. When the shower approached 

 this line, the back ground, on which that beautiful painting of 

 nature was delineated, darkened exceedingly, and exhibited a 

 quadrant, the most brilliant I had ever beheld, with the follow- 

 ing number and arrangementof the colours : red, orange, yellow, 

 green, blue, violet, green, blue, and violet. It was the arrangement 

 of the last three mentioned colours that puzzled me ; forliad the order 

 been reversed, I should have been disposed to refer their production 

 to a partially reflected image of the uriual spectrum. But this 

 was by no means the case, nor did any fainter shade of colour- 

 ing indi^cate an origin different from that of their less equivocal 

 neighbours. The encroachments of the advancing shower left 

 me little opportunity of further observation, only an impression 

 remained on my mind that the breadth of the whole spectrum 

 was not proportional to what might have been expected from 

 the great retrangibihty of the rays which formed this novel addi- 

 tion to it. I am, dear Sir, your obedient servant, 



A. Macome. 



XII. On Rain-Gauges. By Mr. Holt. 



(To Dr. Thomson.) 

 DEAR SIR, * Cork; Oct. 9, 1819. 



In the Transactions of the Wernerian Natural History Society for 

 Decem})er, 1815, Mr. Kerr laid before the Society a model and 

 description of a new rain-gauge, constructed on the principles 

 which seem to have actuated M. Flaugergues to assert in the 

 8th volume of the Bibliotheque Universelle (and thence trans,- 



