45, COBNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 67 



upon the line at different depths ; and in this case the frequent checks and stoppages 

 upon the line during the hauling up, either from the pitching of the ship or in detaching the 

 thermometers as they arrive at the surface, lead to some uncertainty in the results. To do 

 away with all doubt as to the accuracy of the record brought up by each thermometer is the 

 object of the new form of the Standard Deep-sea Thermometer. The improvement is due to 

 suggestions kindly furnished to NEGBETTI AND ZAMBBA by Commander MAGNAGHI, of the 

 Royal Italian Navy. By means of it the thermometer may be attached to any part of the 

 line during the descent ; and after the first regular haul in of from 10 to 80 feet, according 

 to adjustment, any number of stoppages or any amount of line may be afterwards run out 

 without altering the temperature obtained at the commencement of hauling up. Several 

 thermometers can now be fastened upon the line and serial temperatures obtained at any 

 required depth with certainty. 



The apparatus will be best understood by reference to the accompanying figures 

 (Nos. 1 and 2). A is a metallic frame in which the case B, containing the thermometer, 

 is pivoted upon an axis H, but not balanced upon it. C is a screw-fan attached to a 

 spindle, one end of which works in a socket D, and on the other end is formed the 

 thread of a screw E, about half an inch long, and just above it is a small pin or stop P on 

 the spindle. G is a sliding stop-piece against which the pin F impinges when the thermo- 

 meter is adjusted for use. The screw E works into the end of the case B the length of play 

 to which it is adjusted. The number of turns of the screw into the case is regulated by 

 means of the pin and stop-piece. The thermometer in its case is held in position by the 

 screw E, and descends into the sea in this position (Fig. 1), the fan C not acting during the 

 descent because it is checked by the stop F. When ascent commences the fan revolves, 

 raises the screw E, and releases the thermometer, which then turns over and registers the 

 temperature at that spot, owing to the axis H being below the centre of gravity of the case 

 B as adjusted for the descent. Each revolution of the fan represents about 10 feet of move - 

 ment through the water upwards, so that the whole play of the screw requires 70 or 80 feet 

 ascent ; therefore the space through which the thermometer should pass before turning over 

 must be regulated at starting. If the instrument ascends a few feet by reason of a stoppage 

 of the line while attaching other thermometers, or through the heave of the sea, or any 

 cause whatever, the subsequent descent will cause the fan to carry back the stop to its initial 

 position, and such stoppages may occur any number of times provided the line is not made 

 to ascend through the space necessary to cause the fan to release the thermometer. When 

 the hauling-in has caused the turnover of the thermometer the lateral spring K forces the 

 pin L into a slot in the case B and clamps it (as seen in fig. 2) until it is received on board 

 so that no change of position can occur in the rest of the ascent from any cause. The case 

 B is cut open to expose the scale of the thermometer, and is also perforated to allow the free 

 entry of the water. 



The construction of the Thermometer will be understood by referring to Figs. 3 and 4 

 and also to the description given on page 63 (fig. 71) 



Price for NEGEETTI AND ZAMBEA'S New Patent Improved Frame Standard Deep-Sea 

 Thermometer, as fig. 1. 



The Hydrographic Bureau at Washington published lately the following results of a 

 series of observations carried out in order to determine the length, depth, and duration of 

 ocean waves : 



The longest wave hitherto observed is said to have had a length of half-a-mile, and to 

 have spent itself in 23 seconds. During storms in the North Atlantic waves sometimes 

 extend to a length of 500 ft. and 600 ft., and last from 10 to 11 seconds. 



The most careful measurements of the height of waves give from 44 to 48 feet as an 

 extreme limit ; the average height of great waves is about 30 ft. 



These measurements refer to ordinary marine action, and do not relate to earthquake 

 action or other exceptional agencies. 



F 2 



