Mr Scott's Description of a New Steotm- Engine, t§'C. 21 



Art. II. — Description of a New Steam-Engine without a 

 Boiler. By Alexander Scott, Esq. Communicated by 

 the Inventor. 



In the first volume of the Ediiihurgh Journal of Science^ 

 first series, page 267, the following notice was given : That 

 in 1823 a model of a steam-engine was made and wrought 

 without a boiler, and experiments were made with it in pre- 

 sence of several in the immediate neighbourhood, and after- 

 wards in presence of two ingenious mechanics, (brothers of the 

 name of Halliday, who carry on a small foundry near Hadding- 

 ton) who were invited to witness the rapid production of steam 

 without the aid of a boiler. The plan appeared to them very 

 simple and secure from danger, and the experiments so sa- 

 tisfactory, that they soon afterwards commenced mounting a 

 high pressure engine upon this plan, and of a power sufficient 

 for their own works. It was added, that when finished, if it 

 wrought to expectation, a description of the engine would be 

 sent for insertion in the Edinburgh Journal of Science. Be- 

 fore describing the manner of working the engine without a 

 boiler, it may be proper to state the cause which occasioned 

 so much loss of time in the formation of it. All the parts of the 

 engine were executed by one of the brothers at his spare 

 hours ; and while he was carrying on the different parts, he 

 was twice attacked with a rheumatic fever, which made him 

 long unfit for work of any kind. 



When water of a low temperature is forced by a pump in- 

 to a small generator placed over a fire, every stroke of the 

 pump tends to lower the temperature of the whole body of the 

 water. This led to devise a generator by which water of a 

 low temperature can be forced into it without lowering the 

 temperature of the hottest part of the water. In constructing 

 a generator with that property, two truly flat circular patterns 

 of wood were made, having each corresponding projecting 

 parts. In the one pattern a continued spiral groove was cut 

 from the centre to nearly its circumference, the other pattern 

 was left plain. Fig. 1, Plate I. represents the one, and Fig. 2 

 the other. Both these patterns were made twenty-one inches 



