34 



SCIENCE. 



[Vol. X. No. 232 



over the roller W, and then between the rollers G and H. The 

 rollers F and H axe the same size ; but G is larger, and has a 

 ratchet-wheel at its end. E \s s. rod joining D at D'. At the 

 lower end of ^ is a ratchet-catch K, pressed upon by the spring 

 L, which is also fastened to E. 5 is a rod fastened to D, and has on 



its lower end a wide framework 



composed of horizon- 



tal slats. Between these slats pass the indicator or pointer of an 

 aneroid barometer B, and a metal thermometer^. These pointers 

 are made longer than usual, and have attached a needle-point at 

 right angles in the vertical, as shown by P' and P. This whole 

 apparatus is mounted on a frame or board, and put into a basket 

 suspended from the lower end of a balloon. The three wires be- 

 low are fine wrapped wire, and serve to hold captive the balloon as 

 well as to cause the self-registrations to be made, by aid of the 

 battery ^ at the ground. Let the balloon ascend, say loo feet; 

 then put I on 2-3, and N draws D down. This pushes E down 

 (and the ratchet-catch gUdes over the teeth on G), and pushes S 

 down also. This last causes P' and P to puncture the paper. 

 Now open 2-3 and close 2-4 ; then N' draws D up, 5 is pulled up, 

 and the points P' and P are freed. Also K catches on G, and 

 draws off some paper from c, the paper being drawn between E G, 

 over IV, and between G H. Then the holes pricked by P' P are 

 out of the way, and other holes can be punctured at another eleva- 

 tion of 100 feet for the balloon. A fixed pencil is also pressed 

 against the paper at each observation, as a reference-point for the 

 puncture by the inde,\-point. 



For the hair hygrometer we should have another pointer, P". A 

 small anemometer can be suspended from beneath the basket, and 

 kept vertical by means of a weight. This anemometer causes a 

 contact arrangement to close for an instant for evety 100 feet of 

 wind-motion. The two wires from the anemometer terminate at 

 n and 11' , and, when the magnet N' is not attracting the armature, 

 the points n and n' are free. When the current is passed through 

 N', then n comes in contact with 0, and n' in contact with 0' ; o and 

 o' being joined to the wires 4 and 2, which run to the reel at the 

 ground. At the ground we insert a telephone or a galvanometer in 

 the wire 4. 



The normal condition of the apparatus will be with the current 

 passing through N', and the battery X will cause the galvanometer 

 to give a constant reading ; but, for every hundred feet of wind, 

 the anemometer will close its circuit for an instant, and the divid- 

 ing-up of the current at Z Z\>^ including the anemometer in the 

 <;ircuit will cause a momentary deflection of the galvanometer (or 

 will cause a slight sound in the telephone), and the observer can 

 time these with a watch, and get the wind-velocities whenever he 

 wishes them. 



In place of N we could insert a spring, and do away with the 

 wire 3, and probably various other changes would suggest them- 

 selves to any one actually constructing the apparatus. 



Frank Waldo. 



Cincinnati, O., June 27. 



Sea-sickness. 



With regard to the subject of sea-sickness, treated of in an 

 article in Science, June 3, I beg to offer a few remarks. 



As to the causation of the affection, the process is a gradual one, 

 affecting the balancing sense, which is not interfered with in the 

 ■case of iron-plate workers. The sickness affecting these workers 

 is caused by the successive shocks due to the hammering, and dif- 

 fers from sea-sickness in character and causation. 



An article of mine in the Lancet of June 28, 1884, defines sea- 

 sickness as follows : " The altered sensory impressions affecting 

 those at sea interfere with the co-ordination of movements by which 

 the body is adapted to its surroundings, and with the vomiting and 

 other centres in the medulla oblongata. This interference causes 

 sea-sickness." 



The balancing of the body depends on the ordinary sensory im- 

 pressions, and also on what Foster calls ' the afferent impulses, as 

 it were, of a new sense,' from the semicircular canals, arising from 

 variations of pressure in their ampullae. With reference to the 

 recent paper of Dr. James, the following quotation from my article 



above mentioned may be of interest : " In cases where the internal 

 ear has been injured by otorrhoea following scarlatina or measles, we 

 may suppose that the person learns to balance himself without the 

 intervention of this new sense, the absence of which is compensated 

 for in some way ; and it is a curious fact, and one which throws 

 considerable light on the etiology of sea-sickness, that such persons 

 invariably escape this disease. . . . That deafness in itself does not 

 prevent sea-sickness is in keeping with the fact that the afferent 

 impulses from the semicircular canals do not give rise to auditory 

 sensations " {vide Foster's ' Physiology,' 2d ed. p. 495). 



It is reasonable to believe that no structural change takes place 

 in the semicircular canals, due to the motion of the endolymph, 

 else the longer the motions continued, the more marked would be- 

 come the sickness. The altered impressions affect the brain 

 directly, and sea-sickness is prevented by their action from being 

 mollified or nullified by the educated conscious ego. 



As to drugs, atropine has a sedative action on the medulla, etc., 

 and renders the altered sensory impressions inoperative in produc- 

 ing sea-sickness. It should be given in drop doses of the liquor 

 atropine, B.P., in a teaspoonful of water, every hour, till the physio- 

 logical effect of the drug is produced. 



The bromides have also a sedative action on the brain, but, to 

 prevent sea-sickness, must be given in sufficient doses to produce 

 bromism. As this is a serious condition, and one likely to affect 

 the patient's reason and general health most injuriously, the bro- 

 mides should be used with great caution, and only when prescribed 

 and their action watched by a medical man. 



T. T. Reynolds. 



Steamship ' City of Chicago,* Jersey City, July i. 



The Function of Nitrogen in Manures. 



In works on agricultural chemistry it is usual to classify manures 

 or plant-food substances as nitrogenous matter, phosphates, and 

 potash ; but, while the phosphates and potash enter into the sub- 

 stance of every part of the plant, the amount of nitrogen found in 

 the cereals and food-plants generally is inconsiderable. 



A few food-plants contain nitrogen as an essential element of 

 their substance : thus pease contain from two and a half to three 

 and a half per cent, and tea-leaves from five to eight per cent ; but 

 in the case of all these plants it is well known that they are capable 

 of drawing the necessary supply of nitrogen from the atmosphere. 



Without entering on the question of whether the small traces of 

 nitrogen found in the substance of food-plants generally are essen- 

 tial or accidental, or that other question whether all plants requir- 

 ing nitrogen are, like animals, capable of deriving it from the air, it 

 is very safe to infer, from the slight trace of nitrogen found in the 

 cereals and food-plants generally, that the ammonia, or nitro- 

 genous substance convertible into ammonia, which is necessary to 

 secure a good crop, has some other and more important function to 

 perform than that of supplying nitrogen to the plant. It may be 

 doubted, even, whether nitrogen is a plant-food for the cereals, or 

 in any way essential to their proper development ; but hydrogen, 

 the other element of ammonia, is one of the prime constituents of 

 all vegetable substances, and I infer that it is the easily liberated 

 hydrogen in the ammonia that gives it its manurial value. The 

 function of the nitrogen is simply that of a carrier of hydrogen. 



Let me explain. The substance of all trees and plants, wood, 

 stalk, bark, leaves, fruit, etc., is a chemical compound of the three 

 elements, oxygen, hydrogen, carbon. The tree or plant absorbs 

 carbonic acid from the air, which gives it two of the three essential 

 elements, carbon and oxygen. It also takes up water, which is a 

 compound of oxygen and hydrogen, by the roots ; and by the mys- 

 terious chemistry of organic life, the water and carbonic acid being 

 decomposed on contact, the liberated hydrogen and carbon unite 

 with a portion of the oxygen into definite chemical combinations, 

 the new substance arranging its atoms as cell-contents or cell-walls. 

 All the oxygen of the water, with a portion of that from the car- 

 bonic acid, is liberated, and returned to the atmosphere. Given 

 air, water, and potash, and a soil mechanically suitable, and we 

 have all that is necessary to the full and healthy development of 

 timber and fruit trees, flowering plants, and in fact almost every 

 species of vegetation except the grasses, cereals, and principal food- 



