414 Dinhur Castle, its Gardens and Gardeners. 



tions were extended into a field but poorly supplied witli water. In the 

 course of working we came upon a small spring, which the gardener thought 

 would be of great benefit to the cattle if it were conveyed to a proper place 

 for their use, A gentleman happened to be present who held a situation 

 under government, and whose business it was to superintend ground work. 

 His opinion was that it would be useless to expend money upon the spring ; 

 because it appeared so weak, and the field so level, that, when the water began 

 to collect, its own weight would prevent the spring from running. The 

 gardener, however, thought differently. He believed that, however weak the 

 spring might be, it would rise to its level although it had a lake to oppose it ; 

 and the spring, for any thing he knew, would balance an ocean ; or else he had 

 been wrongly instructed. The gentleman was not at all pleased at having his 

 opinion controverted by one whom he considered his inferior ; but both were 

 willing that a temporary dam should be made in order to test their knowledge, 

 and I watched the rising of the water from day to day until it ran over its 

 appointed boundary. The gentleman obtained a lesson which he would 

 perhaps remember all the days of his life, and the cattle obtained water, which 

 was a great benefit both for them and their owner. Sometime after 1 fell in 

 with part of Playfair's Outlines of Natural Philosophy, which gave me a little 

 help on the subject. I also procured an odd number of Nicholson's Journal, 

 containing an article entitled ' A Summary of the most useful Parts of Hydrau- 

 lics, chiefly extracted and abridged from Eytelwein's Handbuch der Mechanik 

 und der Hydraidxk^ These short treatises gave me new views of common 

 things." 



Colin Forbes then began to explain to the other lads the equilibrium of 

 fluids, and taking his spirit level showed Bauldy how to use it. He showed 

 them that it is upon the tendency of all the particles of fluids to come to a 

 level that the making of leveling instruments depends : and, if the person who 

 opposed the collecting of the water had remembered that, if a communication 

 by means of a tube or pipe, either straight or crooked, be made between the 

 water in one vessel and that in another, the surface of both will be at the same 

 level before the water is at rest, and if he had also remembered that the water 

 in the spout of a teapot will balance all the water in the pot, he would never 

 have acted as he did. If persons would accustom themselves a little more to 

 observation and thinking, they would be less liable to fall into blunders. It 

 is no uncommon thing for gardeners to superintend the formation of ponds 

 and lakes in pleasure-grounds, and it is of great importance to know some- 

 thing about the nature and properties of the materials they have to deal with ; 

 for accidental circumstances frequently cause much mischief, not easily 

 repaired. He once knew a flower-garden nearly ruined by the breaking down 

 of a small lake ; gravel was washed upon the ground, and many of the shrubs 

 removed by the force of the water. Whereas, if proper attention had been 

 paid in the erection of the dam, the disaster would have been prevented. He 

 then gave some illustrations of the pressure of fluids, and made them acquainted 

 with the hydrostatic paradox. He laid down the rules for finding the pressure 

 of water upon level and sloping surfaces, and for finding the centre of gravity, 

 and the centre of pressure, as well as the specific gravity, of bodies in general ; 

 and demonstrated the principle on which the siphon works, and its applica- 

 tion to horticultural purposes. He also noticed capillary attraction, and ex- 

 plained to them how glass in garden erections is broken by means of it in 

 winter, when broad overlapping is practised in glazing. He informed them 

 of some of the important offices that are supposed to be performed in nature 

 by capillary attraction, such as the distribution of moisture in the soil, and the 

 rise and circulation of sap in vegetables by means of their fine capillary tubes. 



After having explained that part of the science which makes us acquainted 

 with the proportion of the equilibrium and pressure of fluids, he next turned 

 to Hydraulics, that division of " natural philosophy which treats of the motion 

 of liquids, the laws by which they are regulated, and the effects which they 

 produce." He endeavoured to make them understand that important theorem, 



