VOL. XII.3 PHILOSOPHICAL TRANSACTIONS. 415 



except two long spaces, which are made of sun-dried bricks, and are the hearths 

 above-mentioned, in which the fires are made to heat the eggs, lying under 

 them in the lower ovens. Above these lower ovens are so many others, made 

 of sun-dried bricks, and arched at the top. Where also there are some holes, 

 which are stopped with tow, &c. or left open, as they please, to govern the 

 heat in the ovens below. 



The plan of the upper oven is according to fig. 2. Here, a, is the mouth of the 

 oven, opening on the long entrance ab above-mentioned, b andc entrances into 

 the ovens adjoining, d, e two hearths 3 or 4 inches deep, in which they make 

 the fire to heat this and the oven below. The depth of the lower oven is about 

 24- feet English. The second above 4 feet. 



On Barnacles. By Sir Robert Moray. N° 137, p. 925. 



In the western isles of Scotland, much of the timber wherewith the common 

 people build their houses, is such as the western ocean throws upon their shores. 

 The most common trees are fir and ash. They are usually very large, and with- 

 out branches ; which seem rather to have been broken or worn off, than cut ; 

 and they are so weather-beaten that there is no bark left on them, especially the 

 firs. Being in the island of Uist, I saw lying on the shore a cut of a large fir- 

 tree, of about 24- feet diameter, and 9 or 10 feet long; which had lain so long 

 out of the water, that it was very dry ; and most of the shells that had formerly 

 covered it were worn or rubbed off. Only on the parts that lay next the ground, 

 there still hung multitudes of little shells, having within them little birds per- 

 fectly shaped, supposed to be barnacles. The shells hung very thick and close 

 to each other, and were of different sizes ; they were of the colour and con- 

 sistence of muscle- shells, and the sides or joints of them joined with such a 

 kind of film as muscle-shells have, which serves them for a hinge to move upon 

 when they open and shut. 



The figure of the barnacle-shell is here represented, fig. 3, pi. 12. It is thin 

 about the edges, and about half as thick as broad. Every one of the shells has 

 some cross seams or sutures, which, as I remember, divide it into five parts, 

 nearly after the manner as in the figure. These parts are fastened to each 

 other with such a film as muscle- shells are. These shells hang at the tree by a 

 neck, longer than the shell. This is of a kind of filmy substance, round and 

 hollow, and creased, not unlike the wind-pipe of a chicken, spreading out 

 broadest where it is fastened to the tree, from which it seems to draw and con- 

 vey the matter which serves for the growth and vegetation of the shell and the 

 little bird within it. 



