TRANSACTIONS OF THE SECTIONS. 229 



From these experiments it appears that the " set " decreases with successive 

 applications of the same load. 



This decrease of set also appears to obtain even when the load applied is an 

 increasing one. 



The results obtained from 10 bars are given in Table IV. 



Table IV. 



Average results obtained from 10 unbroken bars with increasing loads. 



Loads 3360 lb. 3-920 lb. 4480 lb. 



Average deflection .... ■341 in. '307 in. -388 in. 



Average set '026 in. •014 in. 'OOS in. 



On a SpJierical Pendulous Safety- Valve. By James Nasmyth, F.E.S. 



On the Investigation of the Steeriny Qualities of Ships. By Prof. Osbornk 



Reynolds. 

 [Printed in extenso among the Eeports, p. 70.] 



On a New Form of Lamp. By E. Lavender. 



The construction of the lamp is a glass lantern 18 inches square, with a funnel or 

 chimney 24 inches high, into which is introduced a jet of steam about ^\ inch 

 across when the pressure of steam is about 201b. to 301b. per square inch; if 

 the pressm-e is less the jet must be larger, if higher smaller, the object of the jet 

 being to create a partial vacuum in the lantern — the consequence 'feeing that the 

 surrounding air is forced through the burner of the lamp and causes a very com- 

 plete combustion of the oil. 



A very brilliant light is produced, which is increased partly owing to the pro- 

 ducts of combustion being continuously removed and a volume of fresh air being 

 introduced. 



The lamp or biumer is constructed for a circular wick, and upon the principle of 

 admitting the air to play upon the outside of the wick, and also by a disk another 

 column is thrown upon the inside of the wick ; another current of air is also 

 carried through the centre of the flame. The metal cap is constructed so as to 

 bring the flame into a centre, through the orifice of which it is drawn by the jet of 

 steam in the chimney. The oil supply is contained in a shallow vessel, which is 

 heated by a jet of steam before being burned, as many of the oils that may be used 

 would become thick in cold weather. 



The results obtained from a 4-inch wick have been equal to a light of upwards 

 of six hundred sperm candles, the cost of which, with oil at 9d, per gallon, is under 

 Irjl. per hour. The oil was supplied by Messrs. Young's Paraffin Light Company, 

 and is a product from shale and is a part of the oil that hitherto has been of 

 little use. 



The cost of burning an open fire, such as is used at many pit-heads, is from ten 

 to twelve hundredweight of coal per night ; it is a most uncertain and dangerous 

 light. 



Whilst the author's lamp was designed for collieries, loading-banks, sheds, 

 sidings, ships, &c., he thinks that it will be of great service to the public. 



On Boiler Incrustation and Corrosion. By F. J. Rowan. 



The importance of the subject is alluded to, especially to marine engineers, who 

 have most keenly felt its difficulties, while the range of interests involved by it is 

 as wide as the use of steam. 



The present state of general information about it being unsatisfactory, we have 

 187G. 20* 



