_Tides_.--The variation of the tides is so slight that navigation is almost unaffected by it. The ordinary rise and fall is from 18 to 24 inches, with an increase of about a third at spring tides. High water is later on the eastern than on the western coast; occurring, on full and new moon, a little after eleven o'clock at Adam's Bridge, about 1 o'clock at Colombo, and 1.25 at Galle, whilst it attains its greatest elevation between 5 and 6 o'clock in the harbour of Trincomalie. _Red infusoria_.--On both sides of the island (but most frequently at Colombo), during the south-west monsoon, a broad expanse of the sea assumes a red tinge, considerably brighter than brick-dust; and this is confined to a space so distinct that a line seems to separate it from the green water which flows on either side. Observing that the whole area changed its position without parting with any portion of its colouring, I had some of the water brought on shore, and, on examination with the microscope, it proved to be filled with _infusoria_, probably similar to those which have been noticed near the shores of South America, and whose abundance has imparted a name to the "Vermilion Sea" off the coast of California. THE POPULATION OF CEYLON, of all races, was, in 1857, 1,697,975; but this was exclusive of the military and their families, both Europeans and Malays, which together amounted to 5,430; and also of aliens and other casual strangers, forming about 25,000 more. The particulars are as follow:-- |Provinces |Whites. |Coloured. |Total. |Population| | |Males.|Females.|Males.|Females.|Males.|Females. | to the | |sq. mile. | |Western. |1,293|1,246|293,409|259,106|294,702|260,352 | 146.59 | |N. Western | 21| 11|100,807| 96,386|100,828| 96,397 | 59.93 | |Southern | 238| 241|156,900|149,649|157,138|149,890 | 143.72 | |Eastern | 201| 143| 39,923| 35,531| 40,124| 35,674 | 16.08 | |Northern | 387| 362|153,062|148,678|153,449|149,040 | 55.85 | |Central | 468| 204|143,472|116,237|143,940|116,441 | 52.57 | | |2,608|2,207|887,573|805,587|890,181|807,794 | 69.73 | CHAP. II. CLIMATE.--HEALTH AND DISEASE. The climate of Ceylon, from its physical configuration and insular detachment, contrasts favourably with that of the great Indian peninsula. Owing to the moderate dimensions of the island, the elevation of its mountains, the very short space during which the sun is passing over it[1] in his regression from or approach to the solstices, and its surrounding seas being nearly uniform in temperature, it is exempt from the extremes of heating and cooling to which the neighbouring continent of India is exposed. From the same causes it is subjected more uniformly to the genial influences of the trade winds that blow over the Indian Ocean and the Bay of Bengal.