42 THE VOYAGE OF THE 'DISCOVERY' 



occasions were rare, and when we got amongst the ice we 

 reaped great benefit from it, for then, as will be seen, it formed 

 a buffer which prevented the heavier pieces of ice from coming 

 into contact with the rudder. 



On the whole, therefore, the hull of the ' Discovery ' was a 

 splendidly strong and well-fortified structure, and the machinery 

 was in all respects equal to the hull. The ship had two 

 cylindrical boilers arranged to work at a pressure of 150 lbs. 

 per square inch, and a set of triple expansion engines. The 

 latter were designed to give 450 indicated horse power, but 

 actually on trial gave over 500. Whilst there was nothing 

 particularly novel in these engines and boilers, many details in 

 connection with them had to be considered with especial care 

 in view of the service for which they were required ; more 

 particularly was this the case with regard to the leads of steam 

 pipes and the position of sea inlets. 



In the shape of auxiliary machinery, besides that in con- 

 nection with the main engines, the ' Discovery ' possessed a 

 small condenser for making fresh water, a small dynamo for 

 supplying electric light, a strong deck winch amidships, and a 

 very powerful capstan engine under the forecastle. In connec- 

 tion with the last-named, and placed close to it, there was also 

 a small auxiliary boiler which on one occasion at least did 

 yeoman service. All these various machines were supplied by 

 different firms, but our excellent set of main engines and 

 boilers were built and placed by Messrs. Gourlay Brothers, of 

 Dundee, and to the energetic manager of this firm, Mr. Lyon, 

 we owe the really novel feature which was embodied in our 

 arrangement for lifting the screw. 



For the benefit of those who are interested in engineering 

 details I may briefly explain this device, as it is certainly 

 worthy of record. As I have said, a lifting screw is a common 

 fitting, but it has always had one disadvantage in the fact that 

 the joint between the shaft and the screw has tended to get 

 loose, and this has caused a very uncomfortable jarring when 

 the engines have been revolving. The fittings in the ' Dis- 

 covery ' entirely avoided this in the following manner : The 



